To accurately evaluate the bending capacity of corroded reinforced concrete beam,we take three corroded reinforced concrete beams of prototype members as research objects,carry out the bearing capacity test and simulation analysis,and put forward a simplified calculation method for bearing capacity of corroded reinforced concrete beam with modified code.By using this method,the average cross-section corrosion ratio of all the steel bars in the same section can be converted from the corrosion ratio of one or several steel bars detected in the field,which can be used to calculate the strength utilization coefficient of the corroded steel bars,and solve the problem of inaccurate calculation of the bearing capacity when the cross-section corrosion ratio of the steel bar is greater than 10%.