The friction coefficient measurement of lubrication liquid by oscillator method has too much trouble for manual operation and data collection.Based on Photoelectric Technology,an automatic measuring apparatus of friction coefficient for lubrication liquid was developed.The structure and measuring principle of the apparatus were introduced.The apparatus was used to evaluate the effects on friction coefficient of lubricating grease by types of base oils,viscosity changes,thickener types and anti-wear additives.The results show that the automatic oscillator method has higher sensitivity as compared with the four-ball method,and the comparability of the friction data of the grease is much reasonable.The developed apparatus can be used for evaluation and comparison of friction properties of the grease,and it is more suitable for the fast selection of grease formulation in research and development of grease.