Abstract: The evaluation data of various fatty acids and their ester derivatives showed that the key factor affecting the anti-wear was the structure of polar groups of the molecules. By molecular simulation method，the effects of polar group structure of anti-wear agent molecule on its physical and chemical adsorption energy, molecular-interaction energy and the anti-wear performance was explored. The results showed that enhancing the adsorption on the friction surface and intermolecular binding energy of the anti-wear agent molecules is beneficial to strengthen the adsorption stability and structural stability of the lubrication film, which helps improving the anti-wear performance of the agents. Introducing small polar groups，such as —OH，near the polar group of anti-wear agent molecule can heighten the adsorption ability and molecular interaction of the anti-wear agent molecules. The anti-wear performance tests proved that after introducing –OH, the anti-wear performance of the agent is significantly increased，which is consistent with the theoretical research results.

Key words: anti-wear agent, polar group, anti-wear performance, adsorption energy, rmolecule-interaction energy