Abstract: The bentonite greases were prepared using T400, T110, 200DN, MVI500,150BS and PAO8 as the base oils, respectively, with bentonite powders before and after ball–milling as thickening agent. The thickness, shear stability, colloid invariability, water resistance, anti-wear and antifriction properties of the prepared greases were investigated. The results show that the performance of ultrafine bentonite grease is improved significantly, compared with the traditional one. And the base oils have huge influence on the performance of ultrafine bentonite greases. The ultrafine bentonite grease prepared with the base oil of T110 has a better shear stability, water resistance and anti-wear property.