Objective To understand time-effect relationship in prehospital emergency care of trauma patients so as to cut down mortality. Methods The data of pre-hospital deaths of trauma pa-tients were collected from 67 Shenzhen Emergency Network Hospitals during 2002-2004 and input into a database established by using Foxpro 6.0.Then, the data were analyzed by software SPSS 11.0. Re-sults A total of 161 364 trauma patients received prehospital emergency call service during 2002-2004 and 3 967 patients died prehospital or in hospital.There were 360.528 and 645 trauma patients died pre-hospitsl in 2002, 2003 and 2004 respectively, accounting for 32.57%, 37.69% and 44.25% respec-tively of whole trauma emergency patients in corresponding year.In 2002, 2003 and 2004 respectively, pre-hospital mortality was 1.15%, 0.88% and 0.99%, ratio of male to female 79.17/20.83, 77.65/22.35 and 71.63/28.37, the death age(29.04 ±13.98), (27.84±18.54)and(29.25±17.06)years old, ratio of traffic trauma to non-traffic trauma 48.33/51.67.26.14/73.86 and 37.98/62.02, the median response time of ambulance in hospital 2, 2 and 1 minute, the median time of ambulance arri-ving at the accident scene 5, 8.5 and 7 minutes and the median time of ambulance to and fro was 15.35 and 30 minutes. Conclusions There is a tendency that the number of the pre-hospital deaths of trauma patients increases, but that the ratio of traffic to non-traffic trauma and mortality decrease.The average age of dead trsuma patients is 10 years younger than that of whole emergency patients in the city of Shenz-hen.The response time of ambulance in hospital shortens, but the time of ambulance arriving accident 8cene and to and fro time of ambulance prolong.