Optical interference technology was used to study the grease film distribution under intermittent motion on a ball-disk bench.The changes in central film thickness and minimum film thickness by influence of entrainment velocity at uniform motion and stop time were investigated.Using Centoplex3 grease in the case of sufficient supply,the comparative experiments were carried out at different stop time and different entrainment velocity at the uniform motion.The results show that thickener fiber clusters exist at the late deceleration stage,the stop stage and the earlier stage of acceleration motion,causing some fluctuations and even sudden changes in the film thickness.With the increase of the stop time,the aggregation of fiber clusters becomes little and the size becomes smaller,but there are always thicker fiber clusters in the contact.At the same time instant of non-stop phase,the larger the entrainment speed,the thicker the central film thickness and the minimum film thickness.During the stop time,the variations of the central film thickness and the minimum film thickness don’t comply with this variation.Due to the presence of thickener fiber clusters,the central film thickness and the minimum film thickness can be increased a little bit by the existence of larger thickener fiber clusters.Grease lubrication is more advantageous than oil lubrication in intermittent motion.