Accident reconstruction cannot be carried out without assumptions. So the assumptions must be examined to determine whether errors exist. In order to make this examination, it is desired to present the assumed accident scenes in a clear manner.In such cases where many vehicles are involved or behaviors of the involved vehicles are complicated, it is difficult to present the accident scenes by means of a two dimensional drawing or a clay model. Three dimensional computer graphics can be used as an effective means of presentation in these cases. Because once the computer models of accident scenes are made, they can be easily observed from any position of view and can be easily remade according to need.The purpose of this paper is to show how a computer graphics is used in the process of accident reconstruction. The case of a serious and complicated accident, which involved many vehicles, is illustrated and the process of the accident reconstruction is explained in order to illustrate this technique.