Abstract: The effect of FRP and reinforcement corrosion on the restoring characteristic of RC columns is a key issue in the seismic performance of existing RC structures. According to the experimental results, methods to determine the restoring force and skeleton curve of RC corroded columns strengthened with hybrid FRP were presented in this paper based on the cross-section analysis of undamaged RC element and Clough hysteresis rule. Results show that the skeleton curve calculated using the linear plane assumption with modification by bar-slip model can still be used as the skeleton curve of RC corroded columns strengthened with hybrid FRP, and good agreement between the calculated curve and the test result was obtained. The restoring force model for RC corroded columns strengthened with hybrid FRP can be established using Clough hysteresis rule with a modification for unloading stiffness. The basic theory for seismic damage rehabilitation and evaluation of existing RC structures were presented finally.