Abstract: The characteristics of fracture roughness of sandstone under shear loading were specifically discussed through the fracture surface scanning visual map， contour map of the distribution of the fracture surface and the fracture surface profile contour， according to the 3D information of fracture roughness of sandstone under shear loading collected by self-developed coal or rock shear-flow coupling test device and 3D scanners. It is showed that the deformation characteristic curves generally were in good agreement， the visual features of fracture surface were different from each other， and the distribution of roughness heights was appromiately accorded with normal distribution. Characteristics of profile along the shear direction and perpendicular to the shear direction are different， and cannot reflect the whole fracture surface features. The analysis of roughness parameters relationship among R_○L， R_○S and JRC suggests that there was a linear correlation between JRC and R_○L， and the linearity of R_○S and the average value of JRC was better than that of JRC and R_○L. So the average value of JRC is more suitable to reflect the 3D characteristics of fracture surface.

Key words: shear load, fracture surface, roughness, 3D;sandstone