In view of the problem that the current structural optimization design method does not consider parameter randomness, this paper proposes the structural robustness optimization design method based on genetic algorithm and sequence secondary planning method. The quality characteristics of structural products are used as the optimization target, and the reliability index of performance functions is used as a constraint to establish a robust optimization design model. The reliability index of its performance function is calculated by the sequence secondary planning method, on this basis, the genetic algorithm is used to make iterative calculation, and the optimal design results are obtained. Finally, a certain type of guide rail gear design as an engineering case is used. It is proved that this optimization design method is effective in reducing the weight of the product and improving the structural robustness.