Foam has been widely used as a mobility control agent for improved oil recovery, gas blocking and acid diversion during matrix stimulation in petroleum industry. For understanding foam rheology in porous media, this paper reports an experimental study on film foam flow characteristics in a vertical straight tube. Foam is treated as pseudo-plastic fluid and its non-Newtonian behavior is investigated based on power law constitutive model. It is observed the film foam flow shows clear shear-thinning behavior, with flow consistency coefficient of K=0.11 and flow behavior index of n=0.62. The apparent viscosity of flowing film foam is under the shear rate of 50s-1, which is 25 times higher than the single phase water.