Abstract: Fracture to ughness of PP/AT Composites was studied by means of the method created by williams, et al. which was developed on the basis of LEFM. By utitizing a simple and economical method in which varying measure scales are required, the fractal dimension of fracture surfaces can be determined conveniently. After relating fractal dimension to fracture toughness, it is found that the fractal dimension increases with increasing fracture toughness. This means that fracture to ughness can be inferred by the fractal dimension of fracture surface.