ANSYS,the software of construction analysis,is used to analyze static and dynamic performances of a XH2408 gantry style numerical control (NC) milling machining center and optimize its construction using the finite element method.First,a finite element model is established and the static and dynamic analysis are completed as constraints and loads applied on the finite element model.It is found that both spindle box and gantry are the worst components of assembly in performance.Secondly,the spindle box and gantry are chosen as objects of optimal design separately,aiming to improve their performance.The optimal plans are accomplished on the basis of the minimum volume for the spindle box and the maximum inherent frequency for the gantry subject to the constrains.Finally,the machine tool improved is analyzed statically and dynamically based on the optimal results of the spindle box and gantry.The results show that optimal design with the finite element method increases static and dynamical performances of the XH2408 gantry style numerical control milling machining center and the technique is effective and practical in engineering applications. ANSYS, the software of construction analysis, is used to analyze static and dynamic performances of a XH2408 gantry style numerical control (NC) milling machining center and optimize its construction using the finite element method. First, a finite element model is established and the static and dynamic analysis are completed as constraints and loads applied on the finite element model. It is found that both both spindle box and gantry are the worst components of assembly in performance. Secondary, the spindle box and gantry are chosen as objects of optimal design separately, aiming to improve their performance. The optimal plans are accomplished on the basis of the minimum volume for the spindle box and the maximum inherent frequency for the gantry subject to the constrains. Finally, the machine tool improved is estimated statically and dynamically based on the optimal results of the spindle box and gantry. The results show that optimal design with the finite element method increases static and dynamica l performances of the XH2408 gantry style numerical control milling machining center and the technique is effective and practical in engineering applications.