Abstract: The nonlinear programming models with stability constraints are established for pre-stressed square concrete column wrapped with different materials, such as PE, HDPE, PVC, steel etc. By introducing the ratio of tube cross-sectional length to tube wall thickness, the cross-sectional characteristics of a composite member are indicated by this coefficient, and the nonlinear programming problem is transferred into the optimal design problem solved directly through the iteration formulas. Finally, by using this method, the calculations of cross-sectional optimization design are carried out for the pre-stressed square concrete column wrapped with different materials under the same capacity condition, and the comparison is made between the optimized design and no optimized one. The analysis shows that the proposed method is simple and practical.