Abstract： By consulting Chinese ancient books and modern medical literatures， analyzes chronic atrophic gastritis (CAG) from the perspective of spleen yin，explores the theory of bland flavour nourishing spleen，and discusses the treatment methods and prescriptions based on it. It is found that various factors can cause spleen yin deficiency，and spleen yin deficiency as a pathogenesis is closely related to CAG in the aspects of transportation and transformation of the spleen. ZHANG Xichun's theory of bland flavour nourishing spleen is based on the framework of bland flavour entering the spleen and stomach and treating yin deficiency mainly from the spleen， and he explains the reasons and advantages of bland flavour to nourish the spleen yin in the aspects of yin-yang and five phases，physiological characteristics of zang-fu organs， anatomy， and medicinal flavours and five natures， thus extending the treatment methods： mainly treating by bland flavour and combining sweet and bland flavours together as well as a variety of corresponding prescriptions. This has unique features in the treatment of spleen yin deficiency，which has a positive clinical significance to treat CAG with spleen yin deficiency.