The purpose of this paper is to summarize and analyze the meaning and clinical significance of professor Xu youjia’s core clinical diagnosis and treatment idea of “harmonizing the spleen and stomach” in pediatrics. He puts forward the academic viewpoint that “the child is the body of deficiency and cold”， explains the necessity of “harmonizing the spleen and stomach”， and holds that when using the method of treating different diseases with the same therapy the pathogenesis evolution and syndrome differentiation should be based on the “spleen and stomach”. Professor Xu youjia’s experience is summarized of treating different diseases with the same therapy by flexible application of the method of “harmonizing the spleen and stomach” in the diagnosis and treatment of common diseases， frequently-occurring diseases and difficult diseases in pediatrics. And two proven cases are presented.