The thin water film flow on the ice layer affecting the three-dimensional (3-D) ice accretion on the upwind surface was analyzed. A mathematic model for simulating the flow was developed. A very thin precursor water film beyond the contact line was introduced to deal with the film flow on the dry surface. To treat with the phenomenon that some water film was blew off the surface behind the ice horn

a computational methodology was introduced that the top part of the water film which exceeding the critical height was blew away. The ice shape contrast and water film flow analysis on the airfoil-plane indicates the rationality of the mathematic model and the feasibility of the computational methodology. The research indicates: icing model involving the water film flow can simulate 3-D glaze ice well and provide the ice layer boundary closer to the experimental result than Messinger model. The water film height on the ice layer is about 10-5m and its velocity is about 10-2m/s.