The effect of a sudden stop on the variation of surface dimple phenomenon of elastohydrodynamic lubrication(EHL)in elliptical contact under simple sliding motion was studied on a rollerdisk test rig using optical interferometric technique with the spherical steel roller fixed in a lower holder.By changing the entraining velocity and load,the transition of a “temperatureviscosity wedge” dimple into a squeezed entrapment of oil film by a sudden stop was investigated,and the pictures were measured using a dichromatic interference intensity modulation (DIIM) software to obtain the midsection film thickness.The experimental results show that as the load increases,the occurrence of the “temperatureviscosity wedge” dimple is earlier and the time when the dimple reaches the center of the contact zone become shorter.When the speed is different,the time of the occurrence of “temperatureviscosity wedge” dimple during a sudden stop is different,but the dimples all move to the center of the contact area.As the speed increases,at the sudden stop stage with the rapid change of speed,the initial oil film thickness is higher,and the oil film thickness decreases rapidly,while at the zero speed stage,the oil film thickness decreases slowly.