The morphological characteristics of rock fracture surfaces are key factors affecting their shear slip failure， and normal stress is an important influencing factor on the morphological characteristics of rock shear fracture surfaces. To study the influence of normal stress on the morphological characteristics and roughness anisotropy of sandstone shear fracture surfaces， double-sided shear tests were first carried out on sandstone to obtain shear fracture surfaces under different normal stresses. Then， the shear fracture surfaces formed in the direct shear test were scanned using three-dimensional optical scanning. Finally， the sandstone shear fracture surfaces under different normal stresses were reconstructed in three dimensions. The influence of normal stress on the roughness height indexes for the shear fracture surface was analyzed. Based on the anisotropic parameters， the anisotropic characteristics of sandstone shear fracture surface roughness were studied. The results showed that the expected value， standard deviation， mean of the roughness height， and maximum roughness difference of the sandstone shear fracture surface increased with the normal stress. The roughness of the shear fracture surface exhibited significant anisotropy， decreasing first and then increasing with the increase of the angle between the shear and normal stress direction. When the normal stress was compressive， the shear fracture surface roughness obtained a minimum value at an angle of 75° ~ 90° to the shear direction. The range and anisotropy parameters of the roughness of the shear fracture surface gradually increased with the increase of normal stress， and the anisotropy characteristics of the shear fracture surface were enhanced. The fractal dimension of the sandstone shear fracture surface was a power function of the roughness.