To investigate the damage of RC frame-shear wall structures under earthquake load，a member importance index based on the generalized structural stiffness was introduced. First，seismic elastic-plastic analysis was made by using software perform-3D. Meanwhile，the rules of energy distribution were obtained for RC frame-shear-wall structures. Based on the deformation and hysteretic energy，a seismic damage model with double variables was built to evaluate the member damage，and floor damage model was developed to evaluate the floor damage based on member importance index. Finally，floor damage degree can be evaluated by comparison between damage index under different peak ground acceleration and index ranges. The results showed that the method reflected not only the member damage degree but also the member importance index having effect on floor damage，and the method was applicable to damage assessment for RC frame-shear-wall structures.