Abstract: Based on the plastic limit analysis theorem and used the minimum total potential energy principle, the assumptions of the Temperature String Modal (TSM) of post buckling for the Steel Plate Shear Wall (SPSW) under fire are summarized, and the uniform solutions of allowable shear force of SPSW are deduced. The post buckling bearing properties of SPSW are researched under fire. The fire resistance limit analysis of SPSW is studied in the petrochemical furnace equipments, for which the fireproof protection is designed. The application and compare with the numeral analysis examples indicates that this method is simple and useful, which can provide a theoretical and practical way for the fire design of SPSW structure.