1920 In May, Cai Hesen and Xiang Jingyu officially got married in Mondani. This simple wedding sensationalized the whole city of Mondani. The people watching and congratulating are not only China students studying part-time and part-time in France, but also many strangers from Mondani. Their wedding photos show that they hold open Marxist capital. The photos show that their union is not only an alliance between men and women in love, but also an alliance in the revolutionary ideal cause, helping each other in the same boat. At the wedding, the two also published a book called "Upward Alliance" and distributed it to everyone. Later, people called their union "an alliance with Cai."

Cai Hesen and Xiang Jingyu have the same name, namely Jin Woo, the pen name of "Cai Xiang League". During Cai Hesen's tenure as editor-in-chief of Guide Weekly, they often used this name to publish review articles in the weekly. Jin Woo is a homonym for "warning". 1June, 922, Cai Hesen drafted "China * * * Producers' Party's Views on the Current Situation" for the Central Committee of the Communist Party of China, which was published in the 9th issue of Pioneer, the central publication of the Communist Youth League. This is the first time that China's * * * production party has publicly put forward the slogan "Down with international imperialism" in newspapers and periodicals.

In modern China, "imperialism" and "warlords" were both imported, while ordinary people in China did not know what "imperialism" was at that time. Hu Shi satirized the slogan as "overseas anecdote". 1922 10, Hu Shi said in the article "China in the world" that the slogan "Down with imperialism" is "like a countryman telling anecdotes overseas, and there is almost no factual basis". In response to Hu Shi's remarks, Chen Duxiu and others wrote an article to refute it, and Cai Hesen also wrote an article to refute it in the Guide. 1September, 928, Li, then Minister of Publicity Department of the Communist Party of China, pointed out: "We still remember that when He Sen and other comrades started to put forward the slogan" Down with imperialism "in the Guide, Mr. Lian was busy laughing at this slogan with a scholar's attitude. However, it is this slogan that has promoted and is promoting the revolutionary struggle of millions of people in China. " 1926, Xiang Jingyu and Cai Hesen broke up in Moscow. Although the "alliance" of living couples is gone, the revolutionary ideal alliance still exists. Later, Cai Hesen learned that Xiang Jingyu was arrested and tried to rescue him. Especially the news of Xiang Jingyu's death, I am deeply saddened. I wrote a biography of Comrade Xiang Jingyu to mourn. At the end of his biography, he wrote: "Great warning, hero's warning, you are not dead, you will never die. You are not a private lover with Sen, you are the eternal lover of the China proletariat! "