Based on Darcy-Brinkman Model, a theoretical study of laminar film condensation on a vertical tube surface with thin porous coatings was carried on. The results show the parameters of porous coatings (including conductivity, porosity, permeability and coating thickness) and the surface subcooling have influence on condensation. Especially, the coating thickness is a key factor. Condensation will be considerably enhanced if the thickness is properly evaluated.