To solve the unfavorable deformation problems of asymmetric RC frame-prefabricated shear wall (AFPSW) structures under earthquake excitation, such as inter-story drift concentration and plane torsion, a seismic strengthening method of attaching external rocking frame was proposed to improve the seismic performance and damage deformation capacity of the AFPSW structure. The dynamic equation of the structural system was derived, the deformation control mechanism was revealed, and the corresponding design method was put forward for rocking frame. To verify the proposed method, the AFPSW finite element model was established and verified based on shaking table test. On the basis of the model, nonlinear dynamic time-history analysis was conducted, and the deformation modes, damage states, and performance improvement of the AFPSW structure with and without reinforcement were investigated. Results show that the drift concentration factor N_DCF and torsion of the strengthened structure were reduced by 20.9% and 53% respectively under peak ground acceleration of 0.62 g, which greatly improved the unfavorable deformation of the structure and reduced the damage level of the system.It indicates that the dynamic equation of the structure was correctly deduced, and the proposed reinforcement design method is effective, which can remarkably improve structural uniformity and seismic performance.