Aiming at the problems of axial compression performance,distribution law and design method of steel sheath and reinforced concrete(RCFST)structure,this paper takes the pile foundation of Chongqing Orchard Harbor Phase II as the prototype,the steel sheath thickness,reinforcement ratio and stirrup ratio as variables to carry out axial compressive test of RCFST short columns with slenderness ratio of 41.Considering the double restraint of steel barrel and stirrups on core concrete,the stress mechanism,stress-strain law and internal force distribution law of RCFST structure are studied by peeling analysis method,and the axial compression bearing capacity formula of RCFST short columns is derived and verified.In this paper,based on the results of the test and analysis,combined with the relevant specifications,the design method of reasonable diameter-thickness ratio of RCFST structure is given.The conclusion is that RCFST structure under axial compressive load is in the state of longitudinal pressure double stress,and its peak stress is less than the yield stress of steel sheath;the calculation result of axial compressive bearing capacity based on“unified theory”is closer to the laboratory physical model test value of RCFST short columns.