Abstract: In order to meet the requirements of grouting reinforcement in micro-fractured rock mass, a kind of high performance grouting material with high strength and low viscosity should be studied. Ultrafine cement, silicon powder, ultrafine fly ash and polycarboxylate superplasticizer were selected as raw materials. The slurry was modified by single factor test and orthogonal test. The results show that the stone strength of slurry can be increased by 8% ~ 34% by adding 4% ~ 12% silica powder in cement. Replacing a certain amount of cement with ultra-fine fly ash can reduce the viscosity of slurry. When the amount of fly ash is more than 20%, the viscosity of slurry will no longer decrease, reaching the limit of action. Polycarboxylate superplasticizer has a significant effect on reducing the viscosity of cement slurry, adding 0.1% ~ 0.5% superplasticizer, the viscosity of slurry can be reduced by 25% ~ 90.6%, the higher the amount of superplasticizer, the higher the water out rate of slurry, the more unstable the slurry. When the water-cement ratio is 0.8, the silicon powder content is 10%, the fly ash replacement amount is 20%, and the water-reducing agent content is 0.3%, the slurry performance is the best. The compressive strength of the stone body of the new type slurry is 22.98 Mpa on 28 d, which is 13.6% higher than that of the stone body of pure cement slurry, and the viscosity is 21.8 s, which is 89% lower than that of pure cement slurry.