Objective To study the epidemiologic characteristics of trauma in the prehospital first-aid in megapolis. Methods The epidemiologic data of 10 654 traumatic patients,including treated by prehospital treatment and emergency treatment from January 2000 to January 2005,were analyzed.Results The proportion of male was 70.96%,adult patients(21～50 years old)79.23%,suburb 62.86%,downtown 37.14%.The patients whose ISS scores surpassed 16 accounted for 37.98%,which caused by traffic accident was 37.74%,by public order 24.39%,by industrial trauma 21.71%.The trauma in the limbs accounted for 67.51%,cephalic and cervical wounds accounted for 58.64%,multiple wounds 41.77%,thoracic and abdominal wounds 39.41%.Three hundred and sixty one were killed on the spot,which caused by traffic accident were 46.81%,by public order 28.81%,by industrial trauma 14.40%.Forty-two percent point six six patients died of multiple trauma,54.07% died of cephalic and cervical trauma,15.79% died of thoracic and abdominal wounds.Conclusion Suburban area gradually became the frequently-occurred areas of trauma in megapolis. The wounded were mainly young adults and had a tendency of juvenility.The majority of damaging and lethal factors were traffic accident,public order and industrial trauma.Some pertinet measures and professional first-aid models may improve the traumatic first-aid level.