This research was to investigate the surrounding rock stability, inner force distribution, and reinforcement of the surge tank lining of Lizhou Hydropower Station on Muli River in Sichuan Province of China. Through secondary development of ANSYS by compiling a calculation program with APDL (ANSYS Parametric Design Language) for the inner force of arbitrary section of the surge tank, the inner forces of the lining structure of the surge tank under different working conditions were analyzed. The distribution map of inner force along the shaft elevation was acquired. Suggestions were proposed for the reinforcement of surge tank lining structure in construction period(fore shaft lining segment) and operation period(shaft lining and base slab reinforcement in loading-control case under maximum surge). The verified width of maximum crack of the lining didn’t exceed the allowable limit, which proved the rationality of the structure and the reinforcement design of the surge tank.             