Ensuring the safety and stability of the panel rockfill dam in the lower reservoir of a pumped storage power plant is essential for the plant’s stable operation, and this is typically assessed using the finite element method. This paper develops a three-dimensional finite element model based on the actual operating conditions of the concrete panel rockfill dam in the lower reservoir of the Henan Tianchi pumped storage power station. Various model combinations—including linear elasticity, nonlinear elasticity, nonlinear contact surfaces, and thin-layer units—are employed to calculate and analyze the static forces on the rockfill material, panels, and joints. The results indicate that the engineering design complies with the design specifications. The calculation results can serve as a reference for the analysis and design of similar projects.