To improve the combination mechanical properties of forging machine bed, three machine tool beds with different web-plate layout were designed firstly, and the finite element analysis for beds was conducted in the CAD / CAE of integrated simulation platform. The best bed design plan was selected according to the analysis results. With the main optimization objective of bed's mass and the secondary optimization objective of first\|stage inherent frequency as well as the maximum deformation, by taking the wall thickness and web\|plate thickness of forging machine bed as design variables, the multi-objective optimization design was carried out on the basis of CAD / CAE optimization design technology. The optimal structure dimensions of machine tool bed were obtained after calculation, which decrease the mass of bed by 6.12%. Meanwhile, the static stiffness and vibration resistance also meet the design requirements. Finally, static and modal tests verified the validity of the optimization design.