Aiming at the problem of complex model and large calculation quantity in the optimization design of machine tool headstock structure,an optimization method was proposed combining sensitivity analysis and response surface model.Taking headstock wall thickness and rib size as input parameters and headstock mass,maximum deformation,maximum stress and first order natural frequency as target parameters,six main variables were selected as optimization parameters by sensitivity analysis.The headstock response surface model was established by using optimal space-filling design and Kriging function,and multi-objective genetic algorithm was used to solve and calculate the response surface model.Finally,the finite element analysis of the improved headstock was carried out to verify the accuracy of the solution.The optimized headstock mass is reduced by 13.58%.