<p>Based on the energy balance mechanism and the ideal failure mode, this study proposes a novel two-phase seismic design method that accommodates both minor and major seismic events, meeting structural strength and deformation requirements. The reinforced concrete frame—corrugated steel plate shear wall connected to beam only (called RC-CSPSW) is decomposed into the CSPSW system and RC frame system. Using the energy balance relationship, base shear forces for both elastic and plastic designs are calculated. Initially, using the elastic stiffness ratio of the two systems, combined with lateral force distribution coefficients, the lateral forces for elastic design are allocated among the structural floors, thus completing the minor seismic elastic design for the CSPSW system. Subsequently, lateral forces for plastic design are allocated to the RC frame system using the shear ratio calculated from elastic stiffness ratio, completing the plastic design for non-CSPSW span frames. Finally, by adding the additional forces from the CSPSW system to the RC frame system, the plastic design of the CSPSW span frames is completed. The two-phase seismic design method proposed in this study is applied to three RC-CSPSW structures through pushover and nonlinear time-history analysis to evaluate their seismic performance and failure modes. The results demonstrate that all three structures achieve controlled damage and adhere to maximum inter-story drift limits, with small residual inter-story drift ratio, indicating excellent post-earthquake reparability. This achievement fulfills the dual seismic performance goals, confirming the applicability and efficacy of the proposed design method.</p>