Abstract: The self-compacting mortar is used to carry out on-site grouting tests on sandstone rockfill materials to verify the controllability of the diffusion range of rockfill grouting and the feasibility of grouting technology. The tests show that the grouting reduces the porosity of the rockfill and has mortar cementing between the rockfill materials, which improves the mechanical properties of the rockfill materials, and the grouting construction technology is simple. The laboratory static triaxial tests are carried out to study the mechanical properties of rockfill, and they are compared before and after grouting owing to the characteristics of different grades of rockfill. The influences of confining pressure and fine particle content on the mechanical properties of grouted rockfill are studied. The strength parameters and deformation characteristics of different confining pressures and gradation characteristics are discussed. The experimental results show that the capability of the rockfill to resist deformation is greatly improved after grouting. And the higher the content of coarse particles, the more significant the skeleton effect. The relatively stable cementing structure can be formed after grouting, and the higher the strength parameters of rockfill, the better its resistance to deformation.