Abstract: The mechanic properties and behavior of 12 concrete-filled short steel tube columns strengthened with carbon-fiber-reinforced polymer (CFRP) sheets wrapped externally as specimens after the effects of different constant high temperatures were investigated experimentally under axial loads with different restriction coefficients. The temperature, concrete compressive strength and number of CFRP layers are the main parameters to investigate. Comparisons were made for the standard section and equivalent sections with one and two layers of CFRP involving the improvements in stiffness and bearing capacity. The static test showed that the effect of constant high temperature results in decreased strength and weakend performance, and the mechanical properties of concrete-filled steel tube columns can be extended significantly by wrapping CFRP sheets externally. Analysis and experimental results including elastic modulus and compressive strength are given to demonstrate the validation of the proposed calculation method.