In order to explore the possibility of self emulsifying ester as the main lubricant of the synthetic cutting fluids,different synthetic cutting fluids were prepared with polyether,tetramer of castor oil and selfemulsifying ester as lubricants.The lubrication,antiwear and antifoam performances of the 3 lubricants in the synthetic cutting fluids were investigated by using four ball testing machine,tapping torque tester and liquid circulating foam testing machine.The results show that the selfemulsifying ester can effectively improve the lubrication and antiwear performances of the synthetic cutting fluids,and its lubrication and antiwear performances are similar to that of tetramer of castor oil.The antifoaming property of selfemulsifying ester is better than that of tetramer of castor oil,and its antifoam performance is equivalent to that of polyether lubricant.