Abstract: Polyether additives are an important branch of water-based lubricants. In this research,cocamide polyoxyethylene (Cocamide-POE) is selected as the additive of water-based lubricants to improve tribological properties of pure water. Firstly,film-forming property is analyzed by NGY-6 nano scale film thickness measuring instrument. Results indicate that its film-forming ability has a substantial improvement over pure water and the film thickness increases with the line speed increasing,but has no significant relationship with the concentration. Then anti-friction,anti-wear,extreme pressure and stability performances are studied with the help of MRS-10A four-ball tester. The 3D surface topography of the ball wear scar is studied by micro XAM interferometric surface profile. The results show that Cocamide-POE aqueous solutions have a good anti-friction and anti-wear property,and the seizure (P_B) value of the Cocamide-POE aqueous solutions (3%) is between 784 N and 834 N,which is larger than conventional polyether additives. Overall,Cocamide-POE is a kind of environment-friendly additive of water-based lubricants with good prospects.