The growth and desorption performance of lubricating oil droplets has an important influence on the micro-lubrication process and the micro-lubrication effect.The growth and desorption behavior of lubricating oil droplets at the capillary outlet under the condition of micro oil supply and gravity environment were studied by means of experiment and numerical simulation,and the effects of capillary pipe diameter and surface wetting characteristics on the desorption performance of lubricating oil droplets were investigated.The results show that the growth and desorption of lubricating oil droplets are the result of capillary force,viscous force,surface tension and gravity,and by reducing the capillary diameter or increasing the contact angle of lubricating oil droplets on the capillary surface,the capillary effect can be effectively reduced, the climbing height and desorption particle size of lubricating oil can be reduced,and the desorption performance of lubricating oil droplets can be improved.When the capillary tube diameter is reduced from 1.2 mm to 0.7 mm,the droplet desorption particle size decreases by 4.5%.While the contact angle is gradually increased from 5° to 90°,the droplet desorption particle size decreases by 9.3%.By using low surface energy materials to make micro-supplied capillaries,the contact angle can be significantly increased.