The　film　formation　of　viscous　solutions　in　spin　coating　is　numerically　simulated　in　this　paper.　The　influence　of　spin　velocity　of　matrix,　coating　volume　of　droplet,　surface　tension　coefficient　and　viscosity　coefficient　on　film　formation　and　its　quality　are　analyzed.　It　is　shown　that　the　spin　velocity　of　matrix　and　viscosity　coefficient　have　great　influence　on　film　quality.　Poorly　set-up　of　spin　velocity　could　bring　film　defects.　It　is　easy　to　cause　bigger　pressure　difference　for　overhigh　viscosity　coefficients　and　also　make　the　film　surface　appear　unstable　state.