Abstract: The drying process of two-component acrylic polyurethane coating was simply treated as that of a binary polymer solvent system in this paper. On the basis of some reasonable assumptions, the species continuity equation for the solvent,the equation for the time dependence of film thickness，the boundary conditions and initial conditions for mass transfer of the solvent were set up by using methods of micro-unit and jump balance. The drying model consists of nonlinear partial equations in time and space domain,so it was solved numerically by the finite element technique. The modeling results were consistent with measurement date.In addition, a kind of skinning could be reasonably explained by modeling.