In order to investigate the seismic performance of railway gravity pier reinforced by steel plate and concrete composite after earthquake, a scale model of pier with reinforcement ratio of 0.5% was made for quasi-static test. The damaged area at the bottom of the model pier was reinforced with steel plate concrete composite. The failure mode of the reinforced pier model was studied by periodic reciprocating load test. The seismic performance was analyzed from hysteresis curve, skeleton curve, energy dissipation capacity, stiffness degradation and displacement ductility, and the finite element model was established for verification. The test results show that: (1) The pier body of the steel plate reinforced pier model is used as the transition zone to avoid the failure surface transfer caused by the concentrated force; (2) The steel plate concrete composite reinforcement can effectively improve the stiffness, energy consumption and bearing capacity of the model specimens, and significantly improve the seismic capacity of the bridge pier. The reinforcement scheme can be used for the restoration of gravity bridge pier after earthquake.