To improve the performance of ultra-fine cement grouts (UFCG), multi-walled carbon nanotubes (MWCNTs) were added into UFCG. The effects of MWCNTs on the strength and grouting properties of UFCG, as well as the bond effect after MWCNTs being added and poured into concrete gap were tested. The results show that the optimum content of MWCNTs (10~20 nm) in UFCG is 0.10% (mass fraction). At this time, compared with blank group, the 56 d flexural strength, compressive strength, and their ratio of UFCG increase by 24.3%, 23.4% and 7.1%, respectively. With the increase of MWCNTs content, the fluidity of UFCG decreases, the viscosity and grouting pressure increase. It means that the grouting property decreases gradually. When the MWCNTs content is no more than 0.10% (mass fraction), the porosity of UFCG is not significantly improved, and the grouting effect is not significantly reduced. The result of splitting tensile test shows that the bond performance of UFCG and concrete is significantly enhanced after adding MWCNTs.