Abstract: The four-level optimized method is used for the optimization design of a cable-stayed lattice structure. The height of the mast is considered as an additional variable so as to expand the optimized scope. The cross-sections of members and cables are optimized by the full stress method. The prestress value of cables is optimized by the improved iterative matrix method based on the objective function of key point displacements. The height of mast is optimized using the complex method and the sensitivity of the mast height to the steel weight of the structure is analyzed. The optimized computation program is compiled using APDL parametric design language of an ANSYS procedure. The program is verified by an engineering example. The results show that the optimization can be achieved after 4 or 5 iterations.