A　calculation　method　for　predicting　the　dynamic　characteristics　of　gas　bearings　is　proposed　to　solve　the　problem　of　inaccurate　solution　to　the　aerostatic　spindle　rotation　error　and　to　reveal　the　internal　mechanism　of　the　film　damping　affecting　the　dynamic　characteristics　of　gas　bearings.　The　method　uses　the　film　damping　model,　and　the　gas　film　damping　coefficient　of　the　air　bearing　is　modeled　and　solved　by　the　micro-perturbation　method　and　the　variable　separation　method.　Then,　the　film　damping　coefficient　is　introduced　into　the　dynamic　model　of　bearing-rotor　system,　and　the　influence　of　the　damping　coefficient　on　the　dynamic　characteristics　of　a　gas　bearing　is　calculated　and　analyzed.　Finally,　a　test　bench　for　measuring　the　gas　bearing　rotation　error　is　set　up,　and　the　real-time　rotary　runout　error　signal　of　the　spindle　is　obtained　and　compared　with　the　theoretical　result.　Experimental　results　and　a　comparison　with　the　rotation　runout　error　without　considering　the　damping　characteristics　of　the　film　show　that　the　value　of　the　spindle　runout　error　calculated　by　considering　the　damping　characteristics　of　the　film　is　closer　to　the　experimental　value　and　the　spindle　runout　error　rate　reduces　by　4.93%-8%.　Therefore,　this　research　may　provide　a　theoretical　reference　for　the　prediction　and　precision　control　of　the　dynamic　characteristics　of　air　bearings.　©　2019,　Editorial　Office　of　Journal　of　Xi＇an　Jiaotong　University.　All　right　reserved.