Nano-copper was prepared by liquid phase reduction method.The high purity and high concentration nano-copper ethanol suspension with nano-copper content approximately 15%~20%,and the average particle size about 95 nm was prepared by using suitable centrifuge enrichment processing.The composite nano friction reducing coatings were prepared by mixing some nano-PTFE and polyacrylic resin together with nano-copper ethanol suspension,and the field make up tests were carried out by coating the coatings on the surface of casing and coupling threads.The results show that the composite nano coatings play the role of friction reducing,which can effectively reduce the direct contact between the steel surfaces.The make-up torque can be greatly reduced and the oil casing thread gluing phenomenon can be improved extremely by applying the coating on the round thread and leaning thread casing connections.