Abstract: It is difficult to design SPSW ( steel plate shear wall) for Chinese current design code． To solve this problem，the finite element software ANSYS was applied to analyze the elastic-plastic buckling behavior under the shear force． The influences of parameters，such as initial imperfection，width to height ratio and width to thickness ratio，on the elastic-plastic buckling of SPSW were compared． According to the results of the analysis，the rational parameter to evaluate the elastic-plastic buckling behavior of SPSW was presented． Based on the FEA data and Chinese current design codes， formulas， used to calculate elastic-plastic instability of SPSW， were fitted． Comparisons with the numerical results showed that the proposed formulas had good accuracy and could be applied in practical engineering．