Abstract: An experimental research was conducted on seismic behavior of stiffened thin steel plate shear walls (SPSWs) considering the effect of vertical load on frame column. Two full-scale rectangular concrete-filled steel tube columns-stiffened thin steel plate shear specimens were tested under low-cycle reverse load. The design of specimens considers two cases of vertical stiffeners with equal spacing and variable spacing. The test results show that the specimens have good ductility and energy consumption capacity when the frame columns are subjected to high axial pressure. The ultimate drift angle of the specimens reaches 1/30. The plastic deformation of the specimens is mainly manifested as the out-of-plane buckling, which satisfies the design concept of “strong column and weak beam”. The arrangement of the stiffeners has no obvious influence on the seismic performance of the specimens. The nonlinear finite element method is further used to study the influence of initial defects and axial compression ratio on the lateral resistance performance of the specimen. The analysis results show that the initial defect distribution mode of the wall and the out-of-plane deflection amplitude have little effect on the pushover curve of the specimens. When the axial compression ratio of the frame column is greater than 0.7, the bearing capacity and deformation capacity of the specimens are reduced. Based on the shear control failure characteristics of the specimens, the calculation method of the specimen’s shear capacity is given. The calculated value is in good agreement with the finite element simulation value, and it is conservative than the experimental value.