The main development direction of helicopter main reducer lubricating oil is to improve it’s load capacity by increasing the viscosity of base oil and using new additives, and increase the reliability of main reducer. On the basis of summarizing the research progress of the helicopter main reducer lubricating oil at home and abroad, this paper points out that our country should develop 9⁃centistokes main reducer synthetic lubricating oil which meets the requirements of MIL⁃PRF⁃32538, and strengthen the research on the lubricating theory and using performance evaluation equipment of aviation lubricating oil so as to promote the adaptability of aviation oil and aviation equipment of our country.