In order to study the mechanical properties of compression and torsion and the seismic ductility under compression and torsion of the composite concrete filled steel tubular short columns with square set square sections , 12 specimens were designed and tested with different axial compression ratios and sectional sizes. Different steel strength and concrete strength are used as parameters for numerical simulation analysis and verify the test results. The results show that after data analysis, the test results and the simulation results are basically consistent. When the strength of the steel is changed, the torsional ultimate bearing capacity increases as the strength of the steel increases. In the case of changing the concrete strength, with the strength of concrete increases, the torsional ultimate bearing capacity increases slightly, and the failure of sandwich concrete exhibits 45o failure. Since the shear modulus of concrete is related to strength, the slope of the elastic phase of the torque-rotation angle (T-θ) curve increases slightly, that is, the stiffness increases. Through data analysis, it can be concluded that the seismic ductility performance under compression and torsion, with a small axial compression ratio 0.2, the displacement ductility coefficient increases first and then decreases as the axial compression ratio increases. In the case of large axial compression ratio 0.2, with the increase of the steel, the ductility of the test piece also increases, while the specimen with a small steel ratio and a small ductility coefficient is prone to brittle failure.