The adjustment and optimization of discipline application code is an important part and breakthrough point of the task of "science foundation discipline layout reform" of the National Natural Science Foundation of China (NSFC). This paper reviewed the historical evolution of the application code of geography discipline, systematically sorted out the problems existing in the current version of the application code for geography discipline, discussed the framework concept, principles and formation process of the new version (2021 Edition) application code system, and emphatically explained the historical evolution, scientific connotation and discipline orientation of the new application code. Compared with the previous versions, the new version of the application code system has the following four unique features: (1) The logic of the system is more reasonable; the first level code name has been changed from "Geography (D01)" to "Geographical Science (D01)". (2) The disciplines are more integrated by setting the second-level application code instead of the three-level application code, which can better reflect the interdisciplinary integration. (3) The fields are more comprehensive; according to the development trend of disciplines and the needs of economic and social development, codes of emerging disciplines and fields such as "disaster geography", "land science", and "geographic big data and spatial intelligence" have been added to the list. (4) More attention has been given to technology, namely, "geographic observation and simulation tools" are identified to encourage the development of key tools and instruments for the research of geographical issues.