Based on the designing requirement of virtual car driving simultaion system, a collision detection algorithm based on the model projection point was proposed referring to Moore and Wilhelms' ideas of the virtual driving simulation system. The algorithm rationally distributes and minimizes the objects which are involved in calculation in different stages, decomposes the struction of scenes and re-organizes the the composition of modles. the experiments and analyses demonstrate that the new algorithm not only reduces the time of the collision detection, but also improves the accuracy of collision detection.