刀具与工作台、夹具的碰撞，刀具过切及碰伤工件成型表面是数控加工中较难解决的三个关键问题。本文提出了一种基于Ｂ－ｒｅｐ表示的碰撞干涉检验算法，用于数控加工过程仿真，能较好地解决上述问题及刀具的少切问题。 Tool and workbench, fixture collision, overcutting and bumping the workpiece forming surface is difficult to solve in CNC machining of the three key issues. In this paper, a collision detection algorithm based on B-rep is proposed, which can be used to simulate the NC machining process and solve the above problems and the problem of cutting less.