Abstract: The concept of tool scanning volume is introduced to describe the process of metion tool,and the method of discrete containment is used to describe the shape of tools, fixtures and workpieces.This enables the simulation of motion interference between tool and workpiece/fixture to become a problem of static interference discrimination between the tool scanning volume and the workpiece/fixture.The discrimination is implemented in three stages.Rough discrimination is first applied if interference of bodyelements exists,fine discrimination and precision discrimination are consecutively applied.Concrete examples prove that the method can greatly shorten the time spent in discriminating the interference between the tool and the workpiece/fixture.