The pH value of superfine cement (SC) grouting material stone body with silica fume (SF) content of 30%~50% (mass fraction, the same below) and water-binder ratio of 14 at different ages was measured by simplified ex-situ leaching method. Meanwhile, the effects of SF content, SiO2 content and theoretical Ca/Si molar ratio of C-S-H gel on grouting material pH value were investigated. The rheological properties and mechanical properties of 60%SC+40%SF low-pH grouting material were examined. In addition, SEM, XRD and TG were used to examine the hydration products and microstructure of stone body. The results show that when SF content is more than 40%, SiO2 content is more than 50% and Ca/Si molar ratio of C-S-H gel is less than 0.8, the pH value of stone body is less than 11.00. The naphthalene superplasticizer (SP) greatly reduces the marsh funnel viscosity of slurry, and the appropriate content of SP is 1.6%. The Bingham model provides a satisfactory description of the rheological properties of slurry. The increase of water-binder ratio has adverse effect on the compressive strength of stone body, so the water-binder ratio should not exceed 1.6. Due to the pozzolanic effect and dilution effect of SF, there is no Ca(OH)2 in stone body after curing for 180 d, and its principal hydration products are C-S-H gel with a low Ca/Si molar ratio and ettringite.