Abstract: By changing the aspect ratio of the circular steel tube concrete short column and the amount of expansion agent used, the concrete expansion agent usage was 0%, 4%, 6%, 8%, and the diameter of the circular steel pipe was 200 mm, 250 mm, and 10 test members were fabricated. It is divided into two groups, A and B. The axial compression test was carried out on the test components, and the failure mode was observed. The stress-strain curves and ultimate bearing capacity of different width-thickness ratios and expansion agent dosages were obtained. The results showed that compared with the ordinary round concrete-filled steel tubular columns, the maximum bearing capacity of the axial compression of Group A was increased by 46.88%, 35.56% and 13.73%, respectively, and that of Group B was increased by 53.13%, 41.58% and 20.08%, respectively. The simulation results of ABAQUS nonlinear finite element software were used, and the experimental results were basically the same as the simulated values. Therefore, when the amount of expansion agent used in concrete was 4%, the maximum bearing capacity of the circular steel tubular concrete column was maximized and the performance was optimal.