Abstract: The Department of Atmospheric Sciences of the National Natural Science Foundation of China (NSFC) took the lead in reforming the application code setting scheme and putting the new version into use in 2020, and since then, it has been continuously improved. The new version of the code setting scheme considers the main research directions and methods and sorts out the main keywords to facilitate the application and evaluation of NSFC projects. This paper summarizes the primary considerations for establishing the research directions and keywords in the subcode D0506 atmospheric chemistry. Simultaneously, the word frequency, research hotspots, and trends in different directions under the subcode are analyzed and discussed. The keyword-based bibliometric analysis highlights existing difficulties and funding priorities with the intention of promoting the development of atmospheric chemistry and relevant areas in the atmospheric discipline.