? Taking sustainable development as the leader, we will promote the research on the regional system of man-land relationship and the development of various sub-disciplines. The theory of man-land relationship is the core theory of human geography. The theory of man-land coordination emerged under the circumstances of rapid increase in world population, scarcity of resources and environmental destruction. As a new view of man-land relationship, its rise has only a short history. The theory of man-land coordination seeks the harmonious and orderly development of man and the geographical environment, which coincides with the essence of sustainable development. Sustainable development involves all aspects of human society such as population, resources, environment, economy, and culture. It is a scientific view of man and earth and the soul of the regional system of man-land relations. In the era of knowledge economy, Chinese human geography should deepen the research on the theory of sustainable development and promote the research on the self-organizing structure, operating mechanism and optimal control objectives of the human-land relationship regional system. This has urgency and practical significance: to study the two major systems of geographical environment and human society as a whole, to study their interaction mechanisms, functions, structures and overall regulatory approaches and countermeasures, so as to rationally and effectively develop and protect the environment. , formulate correct and appropriate land development, land remediation planning and social and economic development strategic services. All branches of human geography have an inseparable relationship with sustainable development. Therefore, it is of great practical significance that the development of each branch should focus on the leading and main line of "sustainable development". As for the emerging sub-discipline of social geography, Academician Wu Chuanjun believes that Chinese social geography should study the regularity of social activities, especially the spatial activities of social groups, as well as regional behavioral geography, living standards research, Crime geography, etc.[3].

In recent years, many Chinese social geography researchers have been engaged in community geography, urban social regional division and social spatial differentiation, rural social spatial systems and rural social life changes, the structure and effects of regional social groups, and urban crime geography and poverty geography. Such research has undoubtedly laid the foundation for revealing the regional differences in Chinese society, the geographical concentration of social problems and phenomena, and the formulation of relevant policies and measures, thereby promoting the sustainable development of Chinese society?