Abstract: A group of planes parallel to cutter axis are defined to cut the model surfaces to be machined and a series of intersecting curves are obtained.Then a set of planes perpendicular to cutter axis are built to trace out the plane areas in which the material should be removed,and the tool path is generated accordingly.The whole tool path is made by properly connecting those on different planes together.With this algorithm the complicated calculation procedures,such as offset,self－intersection checking and Boolean operation of profile loops are avoided.At the same time,the algorithm is also suitable to deal with virtual pocket milling.