Abstract: Based on the introduction of the critical angle, design of irregular plane RC frame-shear-wall structure was achieved using the improved multimode pushover analysis method. First, the critical angle of seismic wave was determined using the wavelet transform in MATLAB. Second, based on the performance requirement from the designed structure, the multimode pushover analysis method and the capacity spectrum were used to calculate the supplement damping ratio, and the corresponding viscous damper was selected and placed properly. Finally, the seismic performance was evaluated using the torsional angle capacity method. The results indicate that the critical angle of seismic wave show significant influence on the performance of the irregular plane RC frame-shear-wall structure. Meanwhile, the structural design based on the improved multimode pushover analysis method can achieve the expected purpose. Furthermore, the method can lead to significantly reduced structural torsional displacement ratio and highly improved structural seismic performance.