Based on earlier experiences with Yangshao cement, we did preliminarily laboratory experiments that revealed that a grouting material consisting of hydraulic lime (obtained from calcinated ginger nuts), metakaolin and silica sand was ideal for treating the cracks developing in sandstone grottoes. Further research also showed that when the grouting material was mixed with 10% of swelling agent, the optimum mixture ratio of hydraulic lime, metakaolin, silica sand was 1∶0.6∶0.4 and ratio of water to cement was 0.5~0.6∶1. Physical, mechanical and durability tests on the grouting material were carried out. The results showed that the hardened grout not only had the merits of large porosity, weak shrinkage and suitable strength, but also had high temperature-humidity cycle resistance, freezing and thawing cycle resistance and a low rate of erosion by salt and alkali. The studied material is suitable for the grouting conservation of sandstone grottoes.