This study aimed to find out the influences of impact speed, vehicle front structure and stiffness on head injuries and discussed the protection measures for skull and brain injury. A parameter study was carried out by using multi-body (MB) dynamic models of pedestrian and vehicles. All the mathematical models were built up using MB program Madymo. The simulation results were analysed and discussed in terms of injury mechanism. The results turn out to be of that vehicle speed, bonnet leading edge height and stiffness of bonnet and windscreen have significant influences on head-brain injuries.