Abstract: Openings in the plate greatly affect the lateral resistant behavior of steel plate shear walls,which have been used more frequently as a lateral load resisting system in the design and retrofit of medium-to-high-rise buildings. Since the lateral stiffness and lateral resistant capacity are the two basic characteristic behaviors in the design practice,this paper focuses on the influence of the opening on the lateral stiffness. This paper firstly presents the experimental results of three steel plate shear walls under the low-cycle reverse load. The satisfying seismic behavior of steel plate shear walls are verified by the test results,and the strength and stiffness of the steel plate shear walls are obviously reduced due to openings. In addition,an elastic elaborate finite element model of the single-story wall panel is developed in order to find the critical factors dominating the reduced lateral stiffness. Furthermore,extensive numerical calculation and parametric analysis are conducted to derive the simplified formulae of thickness reduction coefficient of wall panels with the opening for substituting the reduced thickness wall panel without the opening for the actual wall panel with the opening. The predictions obtained using the proposed formulae correlate well with the numerical results. Finally,some experimental programs of steel plate shear walls are selected to validate the design method proposed in this paper. It can be concluded that the proposed design method in this research can be used reasonably to consider the influence of the opening on the lateral stiffness of steel plate shear walls in the routine design practice.