In order to gain experience and lesson from accidents in a better way, basic steps of accident reconstruction and simulation method is put forward and an analytic method of road segment traffic safety is discussed. This method firstly establishes a road model of accident scene, then establishes an accident participant model (people, vehicle, road block, etc.), then conducts repeated simulations to ensure that simulation results can explain all measured traces on accident scene, and then based on effective simulation of the accident, continue to conduct simulations by changing conditions like people, vehicle, road, etc. in order to study traffic safety of this road segment. Finally, demonstrate steps of this method through a real accident case. The result shows that the analytic method for traffic safety of road segment based on accident reconstruction can intuitively analyze traffic safety problems of road segment on which the accident occurs.