Abstract: Experiments were carried out on eight rubber concrete-filled square steel tubular stub columns subjected to axial loading to study the influence of the rubber replacing ratio and rubber particle size on the compression mechanical properties of the columns. A simplified formula is proposed for calculating the axial bearing capacity of the columns. The test results show that the compressive strength and stiffness of the columns decrease with the increase of both rubber replacing ratio and rubber particle size. The simulation results are consistent with the experimental data, demonstrating that the formula can reasonably evaluate the ultimate bearing capacity of rubber concrete-filled steel tubular stub columns.