In order to achieve the purpose of accident early warning, this paper presents a new method: establish the vehicle accident databases, and combine it with BP neural network technology. First, construct a suitable BP neural network. Second, use the accident feature information to train the BP neural network, then the trained BP neural network can determine the possibility of this specific car accident. At last, send the vehicle information into the trained BP neural network, and it can predict the possibility of this specific car accident. In this paper, the author simulates this method by Matlab7.0.1. Simulation results show that the method is feasible and effective.