Objective To investigate the incidence and influence factors of stress ulcer SU) in traffic injury patients. Methods Clinical data of 362 traffic injury patients were studied retrospectively.Acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ ) score was carried out for all the patients.All the patients had gastroscopy and a comparative analysis was done on the SU patients with or without bleeding and the patients without SU. Results The patients with extensive burn in traffic injury were more susceptible to SU as compared with other trauma patients,with statistical difference ( X2 =7.028,P ＜ 0.05 ).The incidence of SU or hemorrhage was increased with higher APACHE Ⅱ score.The incidence of SU hemorrhage in patients with diabetes or cardiopulmonary disease was significantly higher than that in patients without diabetes or cardiopulmonary disease ( P ＜ O.05 ). Conclusions Traffic injury patients should receive routine gastroscopy.APACHE Ⅱ score has some predictive value for SU or hemorrhage.The incidence of SU hemorrhage is also determined by combined factors of underlying diseases and treatment methods.