Abstract: The stability of seepage in reservoir dams is influenced by various factors and is related to the safe operation of dams.In order to explore the causes of seepage in reservoir dams and evaluate their safety, based on the basic situation of Mishan Reservoir Dam in Weihai City, Shandong Province, in-depth analysis of dam monitoring data was conducted. On this basis, the finite element method is used to simulate the actual seepage conditions of typical dam sections, and the seepage characteristics of the reservoir under three different water level operating conditions are studied. The results indicate that there was no seepage phenomenon in the dam body, which meets the relevant regulatory standards. After comprehensive evaluation, the seepage safety level of the dam was determined to be Class A. This research result can provide reference for the safe operation and management of the reservoir.