Abstract: In view of the high rebound rate, insufficient early strength, poor impermeability and anti-cracking performance and other issues of current grouting materials, a cement-based additive for FZ-H800 grouting was developed. The slurry with different dosage of the admixture was tested. The coagulation time, compressive strength, impermeability and swelling rate of the formulation slurry were measured by“BGF-7 type of needle grouting agent coagulation time tester”, no side-limit pressure tester, impermeability test and self-developed expansion rate test device. The analysis shows that the best admixture dosage is 10%, the initial coagulation time of the formula grout with 10% admixture dosage is 184 s, the final coagulation time is 339 s, and the coagulation time is fast；the strength can reach to 45 MPa in 7 days, and the strength can be close to or reach to 70 MPa in 28 days; impermeability level can reach P8 above; the expansion rate can reach to 0.31. FZ-H800 grouting special cement-based admixture has the characteristics of fast condensation, early strength, high impermeability and micro-expansion.