Nonlinear dynamic damage analysis of joints is one of the important technical issues in seismic safety analysis of high concrete dams. This article employs the finite element time history analysis method, taking into account factors such as the opening of transverse joints on arch dams, infinite foundation radiation damping, and design earthquake loads under normal storage level or dead storage level, design temperature rise or design temperature drop, and the design site response spectrum. The calculation simulation is conducted based on the combination of these factors. The analysis results indicate that the transverse joints in the seismic response of concrete arch dams open and close repeatedly, generating a large opening at a certain instant, but the water stop is not pulled apart. During this process, the overstress at the arch dam abutment is partially released, and the overall stability of the dam body is ensured after the earthquake.