Triethanolamine borate is a new antirust additive of green waterbased synthetic cutting fluid,but its tribological properties in cutting fluid have not yet been reported.The tribological properties of triethanolamine borate as lubricant additive for cutting fluid were studied by using titanium alloy and cemented carbide as friction pairs,and were compared with those of the traditional lubricating additives of glycerol and polyethylene glycol.The tribological properties of triethanolamine borate solution with different content were also investigated.The results show that triethanolamine borate has the same friction reducing and antiwear properties as glycerol and polyethylene glycol.Under relatively high load,the lubrication performance of triethanolamine borate is better than that of glycerol and polyethylene glycol.The friction reducing and antiwear properties of triethanolamine borate is increased with the increase of its content in aqueous solution,when the volume fraction of triethanolamine borate reaches more than 40%,the lubrication performance of the solution is more significant.The results show that triethanolamine borate may be a new lubricating additive for cutting fluid.