Abstract：LI Dongyuan's treatise on the spleen and stomach is the core of his academic thoughts. In order to deeply explore the clinical embodiment of his academic thoughts， the authors consulted and analyzed the main representative formulas in LI Dongyuan's four representative works，namely，Nei Wai Shang Han Huo Lun (Clarifying Doubts about Damage from Internal and External Causes) ， Pi Wei Lun (Treatise on the Spleen and Stomach)，Lan Shi Mi Cang (Secrets from the Orchid Chamber)，and Yi Xue Fa Ming (Medical Discoveries). The authors took the structure of Buzhong Yiqi Decoction as the benchmark， and thoroughly analyzed the structural characteristics of the composition of the relevant formulas， the difference between the addition and subtraction of Chinese medicines and the main symptoms，and their connection，similarities and differences. This paper explored the application law of LI Dongyuan's formula composition and the spiritual connotation of his academic thoughts，so as to broaden the thinking of the clinical application.