The vehicle crash acceleration curve is an important measured data which can represents a time history response of a vehicle during an impact test. To investigate the crash acceleration curve not only can realize the dynamic response and energy change of the impact process, but also able to assess the severity of occupant injury during a crash. The side-impact crash acceleration curve was investigated in this study. The characteristics of the measured crash curve of vehicle impact test can be analyzed to discuss the effect of the crash curve shape on the occupant injury. The shape, amplitude and duration characteristics of curve were discussed herein. Furthermore, a better curve shape to effectively reduce occupant injury was proposed. The trend of curve shape obtained in this study could help evaluate vehicle crash safety and guide the future development of safety technologies.