Abstract: Based on appropriate constitutive models of materials, undamaged and un-strengthened, undamaged but FRP strengthened, and FRP strengthened pre-damaged RC columns are numerically simulated and analyzed by ABAQUS. The reasonable pre-damage simulation method is proposed, and the model change interaction method is adopted to simulate the demolishment and replacement of severely damaged concrete and FRP strengthening. Numerical simulation results are basically consistent with the experimental results. On this basis, the numerical simulation results of three kinds of RC columns are compared. It is found that: the lateral stiffness and bearing capacity of FRP strengthened severely damaged RC columns cannot be fully restored, and the effects of different damage degrees and different FRP strengthening measurements need to be considered. RC columns with different damage degrees and strengthening methods are studied. The results show that the longitudinal and transverse FRP composite reinforcement is effective for the specimens with moderate seismic damage. The repair and replacement of severely damaged peripheral concrete is the key to the performance of FRP strengthened pre-damaged RC columns. Compared with transverse FRP strengthening, the effect of longitudinal and transverse FRP combination reinforcement is better.