Abstract: For the purpose of analyzing the heat transfer characteristics of forced convection condensation for steam-air mixtures in a horizontal tube, based on the heat and mass transfer analogy (HMTA) formulation, a theoretical model was established. By dividing the whole process of heat transfer into the sensible heat, latent heat and liquid film, a correlation for local heat transfer coefficient was obtained. The calculated heat transfer coefficients show good agreement with the experiment data with a relative deviation within ±20%. According to the further research, with the steam condensing inside the tube, the major heat resistance changes from the film heat resistance to the condensation heat resistance on the interface between gas and liquid. Compared with the other heat transfer process, the convective heat transfer between the bulk gases and the interface can be neglectable.