Based on the theory of fracture mechanics, the fracture properties of UPVC sheets under impact load were studied by means of experiments, combined with digital image correlation technology and fracture tests. The results are as follows:Under the same impact energy, the crack initiation time of mixed mode crack is earlier than that of pure mode I crack. The growth speed of pure mode I crack is higher than that of composite crack, and the growth speed of both types of cracks decreases with the increase of crack growth. The pure mode I crack propagates along the pure mode I propagation path. The mixed mode crack propagates along the mixed mode propagation path and is dominated by mode I. It is feasible to apply digital image technology to fracture under impact load.