In order to observe and investigate finite line contact elastohydrodynamic lubrication better under different conditions by experiments,a set of optical interference experimental rig was designed by improving original line contact light interference experiment device.By replacing the crank sliding block with screw putter,the designed experimental rig can turn the rotary motion into a linear motion.The experiments show that the roller can realize the change of the roller in moving speed and motion law,and the clear interference images of elastohydrodynamic lubrication film can be observed in the experiments,and obvious elastohydrodynamic lubrication characteristics can be presented within the roller contact area.When the roller is accelerated in suddenly,the squeeze effect appears more obviously,and the concave is formed within the roller contact area,film is sealed due to stepper motor has very short of pause in accelerating suddenly.The EHL film thickness will increase with the increasing of roller speed.