In order to improve the hightemperature behavior of complex lithium greases,the complex lithium greases were prepared by using 500SN mineral oil and methyl phenyl silicone oil as compound basic oils,using 12hydroxy stearic acid,sebacic acid and lithium hydroxide monohydrate as the raw materials of thickening agent.The effects of the content,type and compound of basic oils on the properties of complex lithium greases were discussed.The best formulation of the complex lithium grease was determined,and thermoanalysis(TGDSC),scanning electron microscope(SEM) and fourball friction tester were used to analyze the complex lithium greases.The results show that complex lithium grease has good comprehensive performance when the content of basic oil is 86%,and the performance of the grease prepared by methyl phenyl silicone oil is better that of the grease prepared by mineral oil.When the proportion of mineral oil and methyl phenyl silicone oil is 4∶6,the prepared grease has high drop point.TGDSC,SEM and fourball friction test demonstrates that the prepared grease has good hightemperature behavior and good friction reducing and antiwear property.