In order to study the effect of homogenization treatment on microstructure and properties of grease,lithium grease was milled by precision three-roller mill with different roller spacing.The microstructure,cone penetration,dropping point,mechanical stability,colloidal stability and rheological properties of the lithium grease before and after milling were systematically studied,and the correlation between the performance of grease and the microstructure of thickener was analyzed.The results show that the milling can improve the uniformity of the lithium grease thickener compared with the non-milling grease.The penetration value of the milled grease decreases significantly.As the roller spacing decreasing,the colloid stability and the structural strength of the milled grease gradually increase,while the mechanical stability decreases.There is a significant correlation between the performance of grease and the microstructure of thickener.The milling can improve the dispersion of thickener.The change in the performance of lithium grease is due to the increase in the specific surface area between the thickener and the base oil because of milling treatment,which increases the interaction force.