Abstract: In order to study the influence of composite restraint effect on eccentric compression behavior of steel-concrete composite square columns with spiral bars, 30 specimens of steel-concrete composite square columns confined with spiral bars, including 15 angle steel specimens and 15 steel tube specimens, were tested under eccentric compression. The failure process and pattern of the specimens were observed, the load-midspan deflection curve and load-strain curve were obtained, and the influence of various parameters on the eccentric compression behavior of the specimens was compared and analyzed. At last, the stiffness degradation law of the two types of composite columns under composite constraints was discussed. The results show that the failure patterns of composite columns are divided into large and small eccentric compression. Internal spiral bars can significantly improve the eccentric bearing capacity and deformation performance of steel-concrete columns, and can also improve the bending stiffness, but the improvement of bearing capacity and flexural stiffness of composite columns will be reduced if the spiral bars are arranged too closely. Moreover, the bearing capacity and bending stiffness of composite columns can be significantly increased by increasing the diameter width ratio of spiral bars and the longitudinal steel ratio of angle steel or steel tube, but the influence of longitudinal steel ratio on deformation performance is far less than that of spiral bars. The stiffness degradation rate of composite columns can be slowed down by decreasing the spacing of spiral bars and increasing the ratio of diameter to width. Additionally, the composite restraint effect on eccentric compression behavior of angle steel reinforced concrete columns is significantly greater than that of concrete-filled steel tubular columns. The calculated results of the analytical formula based on the collapse theory are in good agreement with the experimental results.