Abstract：Fractal interface effect and dynamic character of gravity-type fracture surface sliding befween upper and lower pan of the fracture surface slip under the gravity are studied. The fractal character of the geologic fracture surface is studied. The gravity fracture surface sliding model with self-affine fractal character is established. The fractal interface effect of fracture plane sliding is analyzed by physical and numerical stimulations. The empirical quantitative relationship between the distance of fracture surface sliding and fractal dimension of fracture surface is obtained. The dynamic character of gravity fracture surface sliding is considered and the stiffness criterion of fracture surface sliding is proposed. In the end，the research direction of this special subject is given.
