Abstract: The calculating methods of the initial force andeffective tensile force of prestressing tendon are given in this paper. Thedifferential equation for the prestressed concrete filled steel tubularmember is established, and the formulas for buckling load of the compositemembers are derived by using the theory of elasticity and theenergy principle. On the basis of the strength condition, the limitslenderness ratio is deduced. The numerical examples show that the stabilitybearing capacity of the prestressed concrete filled steel tubular memberexceeding the limit slenderness ratio can be raised by prestressing.