A theoretical analysis of Vacuum Film Deaeration(VFD) based on the characteristics of fluid film on a rotating cone surface is carried out. The motion equation of bubble is derived to find out its relative slip velocity in the flowing film. And the bubbles removal time from the high viscosity liquid is discussed. The thickness model of liquid film on the rotating surface and the residence time of the film flows over the surface are built in this paper. It is found that the thickness and the velocity of the flowing film on the rotating cone surface are the key parameters for VFD; the time of bubble remove mainly includes the growth time and the rest time; the velocity of bubble is slightly lagging behind the main flow; the low angular velocity has little effect on the film thickness; and the time of VFD for flowing film is less than that of static film.