Abstract: A numerical model was put forward based on the coupled Eulerian-Lagrangian formulation. The model eliminates the influence of mesh distortion and the limitation of separation line method in Lagrangian approach. The chip separation from the workpiece machining surface was assumed to be caused by the plastic flow of material. As a result, this model is capable of simulating the vibration cutting process effectively. Under different cutting conditions, calculations of vibration cutting process was performed of Ti6Al4V alloy were performed. Effects of tool vibration was investigated on the cutting force, the machining surface integrity of workpiece, the chip morphology and the behavior of the transition from continuous chip to serrated chip were investigated.