The purpose of this study is to save materials by optimizing the related poles. In this study, the plane and space truss's rod sizes were taken as the design parameters, displacement and stress as the constraints. Uniform Design Method was adopted to approximately optimize a heliostat under wind load, and then approximation functions between objective (displacement, stress and consumption of steel) and parameters were obtained. Finally, this study gave the rod specifications under different conditions. Compared with the existing structure, the optimized structure saves 13.8% of steel. This whole process is simple and reliable.