Objective To evaluate the epidemiological characteristics of traffic accidents on expressways in Shaanxi province. Methods A retrospective analysis was done on the original data of traffic accidents happened on the expressways of Xi'an-Tongchuan, Xi'an-Baoji and Xi'an-Weinan from 1994 to 1999. Results (1) Traffic accidents increased yearly. The traffic accident occurred more frequently in July, August and November, the mortality was high in August, November and December. The peak time of traffic accidents was at 6-8 am and 2-4 pm. (2) The traffic accidents caused by divers accounted for 64.3% (751/1 168). (3) Traffic accidents caused by divers with less than 5 years of driving accounted for 54.2% (633/1 168). (4) Peccancy in the children less than 15 years old on the expressways caused the highest death rate in such group of people. (5) Traffic accidents involved in the truck accounted for 36.3% (776/2 136). (6) Traffic accidents occurred in the fine weather accounted for 64.0% (748/1 168). Conclusions The key to reducing the traffic accidents on the expressways is to take an active and useful measure upon factors such as people, vehicles, roads, surroundings and management.