Geometrical model of virtual machining system was introduced. Based on the analysis of the machining system, it was divided into workpiece subsystem and tool subsystem. Dynamic models of subsystems have been established by means of simplification of machining system. Dynamic analysis and simulation have been done. Model of virtual machining system is the combination of geometrical model and dynamic model. Based on the dynamic analysis and simulation of virtual machining system, conclusion was drawn: (1) In cutting process, as cutter feeds into cutting zone, vibration appears and becomes stronger and stronger. As cutter tends to leave cutting zone, vibration becomes weaker and weaker and disappears finally. The most violent vibration occurs as cutter has engaged into cutting zone and as cutter tends to leave cutting zone. (2) As machining corresponding to dwell of indexing plate, dynamic response is smooth and steady. (3) Vibration will attenuate sharply after cutter leaving cutting zone. The operation of virtual machining system accords with the appearance in real machining process. Properties of product model are very close to those of real machined cam.