Abstract: Vertical machining center is one kind of advanced CNC machining center. The whole casting iron structures have been used for a long time because of the stability. With the development of machine tools towards customer tailor and small-scale manufacturing the welded structures have been gradually applied into forming machine tools. However, the application of welded structures in vertical machining centers with high accuracy is not widespread exists because of thin-wall chattering. In this paper, an innovative design of the tube-plate combination is proposed for the vertical machining center. The static mechanics and modal analysis of the welded structure of vertical machining center is performed by using ANSYS workbench. The results show that the welded structure has good rigidity and can effectively avoid thin-wall chattering. It provides a new method for the design of welded structure of machining centers.