In order to prepare multiwalled carbon nanotubebased bentonite grease with excellent tribological properties,oleic acid was used to modify multiwalled carbon nanotubes (MWCNTs).On the basis of the selfdesigned ultrasonicassisted ball milling test device in the laboratory,the uniformly and stably dispersed suspension of MWCCNTs in PAO6 was successfully prepared,and the bentonite grease with excellent tribological properties was prepared with the suspension as the base oil.The effects of different dispersion methods (ball milling dispersion,ultrasonic dispersion,ultrasonic and ball milling dispersion) on the dispersion stability of MWCNTs were studied,and the changes of grease friction coefficient and wear spot diameter with the mass fraction of MWCNTs were studied.The results show that oleic acidmodified MWCNTs have the best dispersion stability under the combined action of ultrasound and ball mill.With the increase of MWCNTs mass fraction,the friction coefficient and wear spot diameter of bentonite grease is first decreased and then increased.When the mass fraction of MWCNTs is 0.03%,the bentonite grease prepared has the best tribological performance and the smallest specular diameter (0.690 mm),which is 14.5% lower than the Mobil 28 aviation grease (in line with the U.S.military specification MILG81322C,and the specular diameter is 0.807mm).