Objective To observe the characteristic injuries on motor-cyclists for the forensic indentifi-cation in cases of traffic accident. Methods Investigate retrospectively the injuries of motor-cyclists and passengers in 408 traffic accident cases occurred during 2000 to 2002 in Beijing area. Results There were characteristic injuries at motor-cyclist's abdomen, perineum, inner side of thighs, chest, face, neck, front of tibia. They reflect contours of certain components of motor-cycle, but the injuries of passengers can not reflect the components of motor-cycle. Conclusion The characteristic injuries caused by certain components of motor-cycle might be useful for differential diagnosis the motor-cyclists and the passengers in cases of traffic accident.