To the optimization problem of control parameters for the lateral channel of small UAV(SUAV), H2/H∞ robust optimization design is studied with bandwidth as the control quality index and singular value as the robustness index, and analysis is made to the law of parameter optimization of H2/H∞ robust control. An optimization control objective function is constructed by using Gram stability method, and the weighting coefficients of the objective function are optimized. The feasible region of the objective function is restricted by penalty function to obtain the unique solution for system control parameters. Simulations verify the feasibility and validity of the proposed method, and there can be a trade-off between flying control quality and robustness. The controller designed for lateral channel of small UAV utilizing this method has very good control quality and high anti-disturbance performance, which reaches the expected goal.