Abstract: Based on Response Surface Methodology(RSM),the objective function and constraint conditions are approximately explicit to overcome difficulty of sensitivity analysis,the Sequential Quadratic Programming (SQP)model was formed to find optimal shape under displacement and stress constraints.An improved response surface with exact value on the design point is constructed,which eliminates the intrinsic inaccuracy of response surface.The constraint response surface,combined with improved experiment design method,was constructed through few times structure analysis.A second-order evaluation function was set up for each constraint condition.Rational move limits for each design variable were calculated in terms of the relative errors between constraint response surfaces and evaluation functions.The optimization strategy formed with less computation and higher precision.Examples are given to show the efficiency and stability of this optimization strategy.