The effects of corrosion on bending performance of channel steel beams were studied through the bending test of 7 corroded channel steel members. The experimental results show that the bearing capacity of corroded channel steel beam has a good linear relationship with the residual flange thickness, and the residual flange thickness can be used to characterize the degree of corrosion. The load-deflection curves and moment-curvature curves can be roughly divided into two stages: elastic stage and elastic-plastic stage. The curves of some specimens have small slopes at the beginning of loading. According to the experimental study, the formula of bearing capacity based on residual flange thickness and corrosion ratio is proposed. The formula has enough reliability.