Abstract：Chronic atrophic gastritis (CAG) is an important link in the transformation from inflammation to cancer. In Chinese medicine treatment，this disease is treated according to syndrome differentiation based on the theory of Chinese medicine. The purpose of this paper is to explore the etiology and pathogenesis of CAG by analyzing the Chinese medicine theoretical ideas that "the spleen cannot transport the body fluids for the stomach" and "the kidney is the gate to the stomach". It is concluded that the pathogenesis of CAG is deficiency in origin and excess in superficiality； it can be treated from the aspect of spleen and kidney depletion，and attention is also paid to the pathogenic factors of stasis，toxin and dampness.