Modified graphene oxide was prepared by treating graphene oxide (GO) with long chain aliphatic octadecyl amine (ODA).The dispersion stability of modified GO as additive in CD/10W-40 oil was investigated,its structure and morphology was characterized by using IR,XRD,SEM and XPS,and its tribological properties as additive in CD/10W-40 oil was investigated in the fourball tester.The results indicate that the ODA can be successfully grafted on the surface of GO via amidation reaction,the dispersion stability of modified GO in CD/10W-40 oil is increased significantly,and it can remain well dispersed in oil for 30 days without any precipitation.Friction and wear test shows that when the GO-ODA with the mass fraction of 001% can reduce the friction coefficient of the CD/10W-40 oil by about 16%,and the reduce wear scar diameter by 10%.The wear mechanism of GO-ODA is mainly plastic deformation,adhesion wear and abrasive wear.