Since the late 1980s, there have been two main opinions in China academic circles. One thought that the early 20th century, namely 1900, was the beginning of modern world history; Another view is that 19 17 Russian October socialist revolution is the beginning of modern world history. 1. Why did the early 20th century mark the beginning of modern world history and world history entered a new era? With the development of the second industrial revolution (scientific and technological revolution), human society has entered the electrical age from age of steam, social productive forces have increased rapidly, and liberal capitalism has developed into monopoly capitalism. The world market and world economy finally formed, and the world entered the process of modernization among countries. First, at the beginning of the 20th century, a revolutionary breakthrough was made in the field of natural science, and the introduction of quantum mechanics and relativity was of epoch-making significance. In 2005, Einstein completed the General Theory of Relativity, which was "one of the most exciting and tense periods in his life". This is also one of the most rewarding periods. 19 16 completed his summary paper "The Basis of General Relativity". According to the general theory of relativity, space and time are not only related to variable-speed motion, but also to the mass and distribution of matter. It points out that without matter, space and time cannot exist independently. Spatial structure and properties depend on the distribution of matter. It denies Newton's view of time and space in a deeper sense. The establishment of quantum mechanics and relativity is a revolution in physics, which leads to revolutionary breakthroughs in natural science theories such as chemistry, biology, astronomy and earth science. It is these revolutionary breakthroughs in scientific theory that have been transformed into a series of major scientific and technological achievements in the 20th century. Such as the rapid development of atomic energy technology, radio technology, electronic technology, aerospace technology and bioengineering technology. Therefore, the physics revolution in the early 20th century is of epoch-making significance. Secondly, at the beginning of the 20th century, social material production entered the electrical age from age of steam, and the productivity increased rapidly. 19 During the second scientific and technological revolution at the end of the 20th century, science and technology were applied to production, resulting in three revolutionary developments: new energy. The invention of new machines-electric motors and internal combustion engines; The invention of telegraph and telephone, which are tools to transmit information quickly over a long distance, and the basic completion of the second industrial revolution have had another epoch-making and far-reaching impact on human social life. The reaction of the unprecedented rapid improvement of productive forces has also brought about many links in production relations and major changes in people's ideology. Electric power technology is "the industrial sector that can best represent the latest technological achievements and capitalism at the end of 19 and the beginning of the 20th century". [2] From the beginning, Engels keenly saw that the discovery and application of electricity had far-reaching social significance. He pointed out: "The steam engine has taught us to convert heat into mechanical motion, and the use of electricity will open up a road for us, so that all forms of energy-heat, mechanical motion, electricity, magnetism and light-can be transformed into each other and used in industry." Not only "productivity will greatly develop", but also "finally, the opposition between urban and rural areas will be eliminated." This is actually a great revolution. [3] The invention of generators and internal combustion engines marked the great success of the energy revolution. The combination of power technology and internal combustion engine technology has promoted a series of new technological inventions, especially made it possible to manufacture airplanes and automobiles, made heavy industries such as metallurgy, mining and machinery manufacturing develop rapidly, and established a series of new industrial departments such as electrical appliances, chemistry, petroleum, automobiles and aircraft manufacturing. Heavy industry has replaced the leading position of light industry in the world industry, and the electrification of factories, offices, household facilities, transportation and information transmission has made the material production of human society enter an epoch-making comprehensive modernization process. Third, at the beginning of the 20th century, the world market and world economy finally took shape, and capitalism changed from a stage of free competition to a stage of monopoly. The progress of science and technology has promoted the huge and rapid development of productive forces. Great progress has been made in the socialization, specialization and international division of labor of production. Due to the transition of capitalism from free competition stage to monopoly stage, that is, imperialism stage, capital export and colonial division have been completed, and the international division of labor between imperialist suzerain and colonial and semi-colonial countries has formed the international division of labor between industrial producers and primary producers (agriculture, animal husbandry, forestry and mineral products), which has been further deepened and expanded due to the second industrial revolution. Finally, the capitalist international division of labor system was formed. Due to the development of capital export and international division of labor, the world market was finally formed at the beginning of the 20th century. The international division of labor and the final formation of the world market mark the final formation of the world economy. It links the economies of all countries and regions in the world more closely, and brings the production, exchange and consumption of all corners of the world into the capitalist system, making it more international. The economies of various countries and regions have become an integral part of the interconnected and interdependent world economy, and the world economy has entered a new stereotypes period. The final formation period of the world economy is also the completion period of the transition from the free competition stage of capitalism to the monopoly stage. Great changes have taken place in the social economy and superstructure of capitalist countries. The concentration of production and capital has reached a high level. Monopoly organizations dominate the main economic life. At this time, not only the economic model of developed capitalist countries has been replaced by the free competition of monopoly organizations, but also some backward capitalist countries are using monopoly organizations to manage their own economies in order to catch up with developed capitalist countries economically. Bank capital and industrial capital have merged into "financial capital", and on the basis of financial capital, a financial oligarchy has been formed, and the financial oligarchy has controlled the political power. In short, at the beginning of the 20th century, the world entered the stage of monopoly capitalism. Since the early 20th century was the period when the world market and world economy finally formed, the practical significance of one of the important reasons for the beginning of modern world history lies in that the teaching of modern world history should accurately realize that social and economic development follows objective economic laws. Conversely, if people want to promote economic development, they must also follow and apply economic laws. Only by truly understanding these principles can we accurately and scientifically explain the historical process of world modernization. Fourth, at the beginning of the 20th century, Marxism developed into Leninism, and the proletarian revolution entered a new historical period. In July 2003, the second congress of Russian Social Democratic Labor Party was held in Brussels first, and then in London. Bolsheviks (majorities) who supported Lenin and Leninism were formed at the meeting. It marks the emergence of Leninism and the Russian Bolshevik Party. Leninism is of epoch-making significance in the history of international production movement. It is the development of world capitalism to the monopoly stage, that is, the era of imperialism, and the development of Marxism in the era of imperialism and proletarian revolution. Lenin put forward a series of important theories. It pointed out the direction and correct strategic strategy for the proletarian revolution in the capitalist countries with developed material production in Europe and the national liberation movement in the backward colonial and semi-colonial countries in the East in the 20th century. Lenin pointed out that the proletariat should not only lead the socialist revolution in capitalist countries, but also lead the democratic revolution in backward capitalist countries like Russia. We should also strive to lead the national democratic revolutionary movement in colonial and semi-colonial countries; Because of the unbalanced law of economic and political development in monopoly capitalist countries, the proletarian revolution may win in one country or several countries first. Leninism developed the revolutionary strategic slogan of "the proletarians of the whole world unite" put forward by Marx and Engels in the Manifesto of the Productive Party into "the proletarians of the whole world unite with the oppressed nations". The Russian proletariat led the Russian bourgeois-democratic revolution of 1905. Developed Marxist theory and accumulated rich experience in revolutionary struggle. These revolutionary theories and revolutionary struggle experiences are of epoch-making universal significance to the proletariat and the oppressed people of the oppressed nations all over the world. Under the guidance of Marxism–Leninism, Russian Bolshevik Party led 19 17 Russian October Revolution on the basis of summing up the l905 Revolution. Established the world's first socialist country under the dictatorship of the proletariat. Lenin's detailed exposition is one of the ideological sources of Lenin's new economic policy after the victory of the October Revolution, and it is also the scientific conclusion that China is still in the primary stage of socialism since the Third Plenary Session of the Eleventh Central Committee of the Producers' Party of China. History is a mirror of the real society. This is very complicated. Therefore, taking historical materialism as the criterion, determining the beginning of modern world history should not be based on an event, but should be based on "the material conditions that existed at that time, that is, the conditions used by societies of all ages to produce and exchange necessary means of subsistence" as "the ultimate reason for all historical changes" [5]. Accordingly, the above-mentioned "situation" that happened at the beginning of the 20th century is a historical change-a turning point of the times. The early 20th century (1900) is the beginning and upper limit of modern world history. Second, the October Revolution in Russia was the beginning of modern world history. Another view at the beginning of modern world history is that the October Revolution in Russia opened a new era of human history-the victory of the socialist revolution and the establishment of the socialist social system. Therefore, it is the beginning and upper limit of modern world history. Until the founding of New China in the early 1980s, the textbooks of "World History" in China's academic circles, universities and middle schools were deeply influenced by Soviet historiography, so they all held the view that "the October Revolution was the beginning of modern world history". Until 1999, a considerable number of university history textbooks in China still hold this staged view. The syllabus and textbooks of middle school history hold this view in stages. The October Revolution opened a new era in human history, was the first successful proletarian socialist revolution in human history, and was also a historical milestone in establishing a socialist society and advancing towards a capitalist society. Since the ancient medieval world history is mainly the history of primitive society, slave society and feudal society, the modern world history is mainly the history of capitalist society. Then "modern world history" is the history of the establishment and development of socialist society. The First World War and the October Socialist Revolution in Russia are of epoch-making significance to the development of the whole world history. From the perspective of the whole world, it is a turning point in the development of capitalist society to socialist society and the threshold of modern times, so it is the beginning of modern world history. Lenin pointed out: "We have established a Soviet-style country. This has opened up a new era in world history, and the era of proletarian political rule has replaced the era of bourgeois rule. " [6] Mao Zedong pointed out: "The road of the October Revolution is fundamentally a bright road for the development of all mankind." [7] This is because the victory of the great October socialist revolution has made the basic contradictions in the world, except the contradiction between the proletariat and the bourgeoisie in imperialist countries, the contradiction between colonial and semi-colonial countries and the contradiction between imperialist countries, and the contradiction between capitalist social systems and socialist social systems. The existence and development of these world basic contradictions constitute the basic content of modern world history. The modern history of the world is to study the dynamic relations of these contradictions, that is, their development, changes, mutual relations and social economy formed on the basis of these contradictions. The evolution and development of national politics, science, culture and ideology. Because the October socialist revolution in Russia is the starting point of the socialist social system with world historical significance, a great turning point from the capitalist social system to the socialist social system in human history, and therefore the beginning or upper limit of modern world history. The outbreak of World War I was the result of unprecedented intensification of contradictions among imperialist countries. The worldwide imperialist war has further deepened the political and economic crisis of imperialism, and the revolutionary conditions in some imperialist countries are ripe. Faced with such a rapidly changing international situation, proletarian political parties in various countries urgently need to solve the problem of how to scientifically analyze the basic contradictions in the world and the characteristics of the development of the times. How to understand the essence of imperialism, how to launch and lead the proletarian socialist revolution and the colonial and semi-colonial national democratic revolution. Lenin developed Marxist theory, made a scientific analysis of imperialism, and thought that imperialism was the monopoly stage of capitalism and monopolized capitalism. Monopoly is the fundamental feature of imperialism. Lenin also scientifically revealed the unbalanced law of imperialist political and economic development. Since it is unbalanced, there will be weak links and weakest links in imperialist rule, and Russia is the weakest link in imperialist rule. Lenin pointed out that by World War I, imperialism had made all contradictions of capitalism extremely acute, and proletarian socialism could first break through the weakest link in imperialist rule. In one country or several countries, victory comes first. Lenin formulated the theory and strategy of proletarian socialist revolution in the era of imperialism, personally led the great October Revolution in Russia in 19 17, and achieved brilliant victory. Practice is the only criterion for testing truth. The victory of the October Revolution and the subsequent new economic policy proved that Leninism developed Marxism scientifically and accurately. At the same time, it also proves that the second international opportunism deviated from Marxism. As Lenin pointed out: "Imperialism is the eve of the proletarian socialist revolution. Starting from 19 17, it has been confirmed all over the world. " [8] Therefore, the victory of the October Revolution is also a symbol of the scientific nature of Leninism, which enables it to spread widely all over the world and become the proletariat of all countries in the world. It is accepted by people in colonial and semi-colonial countries. The proletariat in Marxism–Leninism and other countries combined with the revolutionary people and ideologically defeated the second international opportunism. In this sense, the October Revolution opened a new era of proletarian socialist revolution and national democratic revolution in colonial and semi-colonial countries. Therefore, the October Revolution in Russia was determined by historical materialist historians as the beginning or upper limit of modern world history. After the victory of the October Revolution, Lenin died prematurely shortly after he put forward the new economic policy. Practice has proved that Lenin's new economic policy and its ideological principles have far-reaching significance for the establishment, consolidation and development of the socialist social system. However, Stalin failed to follow and adhere to Lenin's new economic policy and its ideological principles in the process of socialist construction in the Soviet Union. 1997 The 15th National Congress of communist party, China, "clearly put forward the scientific concept of the primary stage of socialism in the Party's program", which is a reflection on Marxism–Leninism, including the great and brilliant development of Lenin's new economic policy and its ideological principles, and will have far-reaching significance for the development and growth of the socialist cause. To sum up, the author believes that the above two views on the beginning or upper limit of modern world history are all from the perspective of historical materialism to analyze the historical stage. The academic view that the October Revolution is the beginning of modern world history emphasizes the significance of the new turning point of the socialist revolution and the establishment of the socialist social system. Therefore, in our actual teaching process, we should pay attention to combining "those conditions" at the beginning of the 20th century with the social and historical background of the preparation period for the October Revolution. At the same time, when talking about the historical process of "the establishment and construction of socialist social system", we must take the theory of "the primary stage of socialism" as the guide, so as to continuously improve the ideological and scientific nature of this part of the teaching content.