Abstract: At present, the pure cement grouting material can no longer meet the actual needs of grouting reinforcement of fractured rock mass in deep roadways. Therefore, the pure cement slurry is modified by adding sodium silicate, expansion agent and fly ash to obtain a high-performance composite slurry that can meet the actual needs of the site. The orthogonal test method and matrix analysis method are used to analyze the change law of its macro performance and the optimal ratio of the composite slurry, and the microstructure is further analyzed by XRD and SEM. The research results show that the combined action of sodium silicate, expansion agent and fly ash can effectively enhance the performance of cement slurry in all aspects. Sodium silicate has a significant effect on the basic properties of the slurry studied, increasing the amount of sodium silicate can effectively shorten the slurry setting time, but too much will cause the hydration reaction of the slurry to be insufficient, reducing the fluidity of the slurry and the compressive strength of the stone body ; the expansion agent mainly has a great influence on the slurry stone rate ; the fly ash has a promoting effect on the fluidity of the slurry, and has little effect on other properties. By using the matrix analysis method, the optimal ratio of slurry is obtained: water cement ratio is 0.8, sodium silicate content is 2%, expansion agent content is 4%, fly ash content is 5%; sodium silicate and expansive agent react with Ca（OH）₂ to form a large amount of C-S-H gel and AFt crystal to fill the internal pores. In the later stage of hydration reaction, fly ash reacts with pozzolanic reaction to form more C-S-H gel covering the surface of cement particles, which further improves the mechanical properties of composite slurry.