As the basic unit operation in chemical industry, drying is the key process in chemical, food and other related industry process. A lot of modeling methods and simulation technology has been used to reveal the heat and mass transfer process The parameters of modeling are very important because the simulation results are decided by them. The mass transfer coefficient is condition boundary that is very difficult to gotten. Based on the theory of heat and mass transfer, a coupled model for the porous medium vacuum drying process is constructed. The model is implemented and solved using COMSOL software. The parameter sensitivity analyses of mass transfer coefficient were then examined. The temperature, pressure and moisture characteristics were shown.