Abstract:The machining accuracy of NC fixed beam gantry machine tool is influenced by many factors, including parts manufacturing, assembly, material stiffness damping, vibration and cutting thickness.Inorder to raise machine tool's machining precision, machine tool’〖KG-*2〗s dynamic modal was set up based on Lagrangian dynamic principle. By analyzing the freedom of beam and lathe bed, kinematic modal was set up.By using ADAMS software, the relationship of machine tool’〖KG-*2〗s cutting force and movement was simulated,and the influence of different instantaneous cutting force changeon displacement and speed was contrasted.The results show that: when machine tool’〖KG-*2〗s cutting thickness increases, the cutting force, cutting speedand cutting acceleration increase, the changes of the cutting speed and acceleration lag the changes of cutting thickness and cutting force. The simulation results accord with the actual machine tool processing, and it providereference formovement analysis.