Abstract: The main causes and forms of traffic accident happened on the expressway are analyzed, and its developing trend is predicted. A prediction equation to estimate the number of accident events per 100 km is formulated. The findings demonstrate that the traffic control under the conditions of speed exceeding, early stage of traffic opening, and the bad weather should be strengthened. Analysis concludes that although as a whole the trend of traffic accident is declining, the absolute number of accident events will be continuously increasing, while the number of accident events will be gradually decreasing. Among the traffic accidents, most of them are unilateral, speed exceeding is the main cause, and the rear hit is the most common form. At the early stage of traffic opening and under the bad weather, the events of traffic accident will rise obviously.