Abstract: In view of the high frequency of traffic accidents in Beijing, the paper analyses the mechanism of road traffic accidents using traffic conflict theory, and discusses the process of road traffic accidents based on the analysis of road traffic safety situation and accident characteristics. Then from the point of view of safety system engineering, the causation of road traffic accidents is analyzed by applying active/latent model. The importance of management factor is also emphasized. Finally, based on the road traffic situation in Beijing, the paper discusses control strategy for the improvement of road traffic safety by applying 3E measures. The person's unsafe acts and the unsafe state of things in road traffic system might be avoided through such measures as increasing punishment for illegal acts, establishing safety culture, setting up emergency system for road traffic accident and employing Intelligent Transportation System. And thus, the level of road traffic safety in Beijing will be enhanced.