Abstract: Dye coating is the key part of the replication process ofrecordable optical discs. A simplified model of the coating process isgiven on the basis of experiments and the dye coating process is studiedwith the rotating disk theory. The motion equation, boundary equations andcontinuity equation of flow for the dye film are derived, taking intoaccount the topography on the substrate and the interface slip between liquid andsubstrate. The governing equation is finally obtained.