The stress sensitivity of permeability is always an important research topic in the area of tight oil and gas reservoir development. Six fractured samples were prepared from the downhole core samples in the ultra-deep tight sandstone gas reservoir，which were used to conduct the stress sensitivity evaluation experiment in the ultra-deep tight sandstone reservoir. Before and after the experiments of stress sensitivity，laser scan imaging was made on fracture wall. SEM was used to observe the micro-structure of the fracture wall. The research results show that the stress sensitive coefficients of the fractured samples of the ultra-deep tight sandstone reservoir range from 0.41 to 0.72，and the degree of stress sensitivity is from medium and weak to strong，which is significantly lower than that of the typical tight sandstone reservoir in China. The results of three-dimensional laser scanning imaging present that sand particles drop off from the fracture wall before and after stress sensitivity experiments. SEM image shows that the structure of most of the fracture wall is loose and weak before the experiment. During the stress sensitivity evaluation experiments of the fractured samples in the ultra-deep tight sandstone reservoir，the sand particles are separated from the walls of fractures under the effect of erosion，which is caused by drag force and particle erosion. Under the effect of drag force，the particles move and deposit in narrow place of the fractures.Due to a certain strength of particles，the deposited sand particles play a role on propped fractures with the increase of effective stress，which can weaken the stress sensitivity to some extent. The degree of influence of sand production from fracture wall on decreasing stress sensitivity are different for fractures with different widths. The degree of weakening effect for fractures with medium width，relatively large width and relatively small width falls in turn.