Abstract: According to existing correlation between heat and mass transfer, the condensation process of steam with air was successfully modeled by applying a user defined function (UDF) added to the commercial computational fluid dynamics (CFD) package. Moreover, the model was used in two kinds of experiments, covering a total of 10 sets of experimental conditions. Calculated profiles of temperature, air concentration, and velocity components were compared with experimental results and discussed. The simulation results indicate that there is a good agreement between the experimental results and the model prediction results. The distributions of velocity and temperature got from the simulation show a meticulous simulation of the air distribution in steam condensation process.