Composite nanocopper/PTFE friction reducing coating was prepared by adding some suitable amount of nanoparticles in a highpurified and highlyconcentrated nanocopper suspension,with epoxy resin as a binder.By coating to the phosphate layer surface of the P110 coupling,the friction reducing performance of the coating was investigated on a friction and wear tester,and its galling performance was investigated by full scale makeandbreak tests of P110 long round thread casing.The results show that the highly permeable coating can penetrate into the phosphate layer to form a layer of firmly attached antifriction nanoparticles composite copper after curing.The layer is acted as the composite friction reducing effect similar of copper plate and nano ball,which can greatly reduce the makeup torque of casing thread,thereby can effectively improve or even eliminate galling of the high grade material oil casing.