Abstract: The optimization of engineering structures plays a great role in saving infrastructure investment, improving structural effectiveness, and promoting energy conservation and emission reduction. The special industrial processing method of cold-formed steel meets the optimization requirements starting from the section level. The stiffening optimization of cold-formed C-section is provided. Based on the traditional calculation method of elastic buckling performance and the deformation characteristics, the new mode identification method of finite strip is improved to overcome the deficiency of complex cross-section mode identification, and the modified finite strip program based on deformation is compiled. Based on the improved elastic buckling results of finite element method, the complex stiffening section direct strength method is modified. Based on genetic algorithm, the optimization program is developed, and the optimization results of corner stiffening, hat stiffening and complex curling stiffening are provided. The optimization method provided in this paper can provide a convenient way to improve the material utilization efficiency and reduce the construction cost.