In order to study the effect of two phases of hydroviscous drive on the fluid transmission characteristics of the friction film, also to reduce the two phase flow and improve the ability of the oil film to transfer shear torque, the flow field of oil film based on the VOF model was simulated numerically by fluid dynamics simulation software. The production and development rules of two phase flow regions in oil film flow field were gotten. The results show that the oil groove is the main area that produces two phase flow, and the air occupies a volume ratio of 1 to the side transition position of the oil groove near the outer diameter.What’s more, the production of two phase flow regions is mainly influenced by fluid pressure, and its production starts from near the outer diameter and gradually develops towards the inner diameter. The volume of air in the oil film flow field decreases with the increase of oil supply, but increases with the increase of rotational speed. The oil film transmitted torque increases with the increase of oil supply and input speed.