To get an accurate prediction and analysis results of static and dynamic characteristics of the whole machine tool, finite element model should consider adding characteristic parameters to each pair of the combined interfaces when being built. Taking XDK650X engraving and milling machine as an example, integrating the combined interface parameters into the whole machine tool model with the help of finite element method, the dynamic model contained combined interface characteristics of the whole machine tool was built, and investigation on static and dynamic characteristic were carried out. Then, the relative stiffness between the tool and the platform was analyzed by using harmonic respond analyzing method. It was concluded that XDK650X engraving and milling machine has bigger static stiffness in three directions compared with other similar machines, but has comparatively smaller static stiffness in X direction, a bigger relative vibration amount between the tool and the platform in Y direction. Therefore preponderant natural frequency should be avoided in usage, the static stiffness in X direction and the dynamic stiffness in Y direction need for enhancement in structural optimization.