Abstract: The machine tool cross beam is an important main body bearing structure of the machine tool. The static and dynamic characteristics of the cross beam of the DVT series lathe directly affect the machining accuracy of the lathe and the service life of the consumable parts. Simulation optimization is an effective method if the design cannot be verified by the physical operation of the machine tool parts. In this paper, the working characteristics of the lathe are simulated by means of static analysis and modal analysis of the optimized front beam. The analysis results show that the weak position of the cross beam of the DVT series lathe occurs in the middle of the cross beam, then the relationship between the number and thickness of cross beam ribs and the static and dynamic characteristics of the cross beam is analyzed by analytic hierarchy process and grey correlation method. After the second optimization design is implemented according to the analysis results, the optimal design scheme of the cross beam is finally obtained. The optimization design conclusion shows that it is an optimal design plan when the number of cross beam ribs is 5, the thickness is 10 mm, and the spacing distance between the ribs is 340 mm. After optimization, the cross beam mass is reduced by 117 kg, the stress is reduced by 18%, and the deformation is reduced by 0.01 mm, and the first 3 natural frequencies have been improved to a certain extent, and the optimal design effect is significant. This research method provides a new design idea for the optimal design of machine tools.