Aiming at the weaknesses of CNC milling machine bed,a method was presented based on sensitivity analysis and design of experiment.The finite element model of the bed was established,and static and modal analysis was carried out under the condition.BoxBehnken experiment design method was adopted to carry out sensitivity analysis and establish the response surface model.The multiobjective optimization algorithm was applied to optimize the model and combined with the production technique to determine the best optimization scheme.The analysis results show that the maximum deformation of optimized bed is reduced by 20.8%,the first three natural weighted frequencies is increased by 13.3% and the weight is decreased by 3.3%.Compared with the original design,The new design provides a new idea for the design and optimization of the bed.