Abstract: The auther has made a theoretical study of skull injury caused by blunt weapons which falls within the scope of forensic science, from the standpo- int of biomechanics, and has also carried ont relevant experiments. Discuss- ion has been made about the mechanism of various types of skull injury by applying the theory of shells. The transmission of the momentum and the effect of the neck cushion during the process when the blow is dealt have also been analysed. Experiments show that the shapes of injury vary with the transmission of the impact of the blow and the force of the blow relati- ve to time. Higher peak striking force and shorter time lasting appeared to the brittal skulls, and otherwise to the tenacious ones.