Abstract: Finite element models for axially-loaded square CFT (concrete-filled steel tube) columns were proposed using the program ABAQUS. The effects of material nonlinear constitutive relationship and the variation of Poisson’s ratio under loading were taken into account. The contact pressure between the tube and the core concrete, the axial stress distribution of the core concrete under loading and the constraint of the tube to the core concrete were analyzed. The load-deformation curves of the axially loaded square CFT short columns were obtained, which agreed well with experimental data.