Abstract: Grouting is the most commonly used technique to improve the quality of fractured rock mass. According to the single property of grouting effect evaluation, the change of RMDI of rock mass integrity index before and after grouting is studied based on the calculation of rock mass integrity in borehole images. The calculation of fracture parameters such as occurrence, width in the borehole images is described. The characteristics of the fracture are divided into three types, which are not filling, half filling and filling by image recognition. Based on the exponential density function of the integrity of rock mass, the formula for calculating the integrity index of rock mass is established. The corresponding relationship between RMDI and rock mass integrity is summarized. Statistical analysis is made on the change of RMDI before and after grouting. The results show that the integrity of rock mass has obvious improvement through grouting, and the grouting effect is obvious. Finally, a comprehensive comparison is made on the results of the pore wall images and the water permeability of some typical sections. The fractures are well filled, and it is further verified that the effect of the grouting treatment is obvious. It is feasible to evaluate the grouting effect through borehole images and borehole wall integrity index, which can make up the single property and limitation of the evaluation basis of pressure water test results.