The safety of arch dams is greatly affected by the nonlinearity of the concrete. This paper introduces the basic theories on concrete constitutive models, analyzes the incremental energy dissipation function of concrete in the plastic process, and derives an elastic-plastic constitutive model for concrete based on thermodynamic principles. The proposed model was applied to examine the dynamic nonlinear seismic responses of an actual arch dam, and compared with several other models. Besides, the effect of strain rate on the concrete performance was also discussed in details. The research findings provide a reference for the safety evaluation of arch dam design.