Abstract: Lithium lubricating grease containing nano-mesoporous SiO₂ was prepared by using SiO₂ with different morphologies and pore structures as additive. The effects of morphology, pore structure and mass concentration of nano-mesoporous SiO₂ on tribological properties and rheological properties of lithium grease were investigated by Anton-paar NHT3 nano-indentation tester and Anton-paar MCR302 rotary rheometer. The results show that the spherical nano-mesoporous SiO₂ additive reduced the tribological coefficient more effectively, strengthened the skeleton stability, enhanced the thixotropy, anti-shear ability and thermostability of greases. Under low and moderate shear rate, the rheological experimental data was fitted, and a new grease rheological model was proposed, containing nanoparticals mass concentrations parameter.