In order to study the evolution law of the safety factor of gravity dams on soft rock foundations, a shear strength parameter inversion method of structural plane based on monitoring data was proposed. By establishing a time-varying model of shear strength parameters and applying a partitioned finite element-interface element hybrid algorithm, the dynamic evaluation of the long-term anti-slidingstability of gravity dams was achieved. The verification results of engineering examples show that the proposed method effectively reflects the true variation of engineering parameters, significantly improves the accuracy of analysis results, and ensures dynamic evaluation of the engineering safety factor.