A summary is presented of progresses that have been achieved since the 1930s in the research on soil nitrogen(N)in China,covering 1)nature of soil N and soil N fertility,2)N in organic manure,3)the fate and yield-increasing effect of chemical fertilizer-N app lied to agricultural fields,4)impacts on the environment of the losses of chemical fertilizer-N applied to agricultural fields,and 5)N balance in the agricultural ecosystem.It is obvious that the research benefits much from the progresses made in other relevant disciplines. And it is,therefore,stated with emphasis that the guiding ideology of the researchin China must give high attention to harmonization and in tegration of high-yield and environment protection.