The　dynamic　characteristics　of　the　gas　film　of　an　aerostatic　spindle　primary　affect　workpiece　waviness　in　ultra-precision　machining.　To　improve　the　machining　accuracy　of　the　machine　tool　and　provide　a　firm　theoretical　basis　for　the　design　of　an　aerostatic　spindle,　a　simulation　model　combining　transient　computational　fluid　dynamics　(CFD)　analysis　and　transient　dynamic　analysis　is　established　in　this　study　to　investigate　the　dynamic　characteristics　of　the　spindle　under　unstable　operating　conditions.　Based　on　a　large　eddy　simulation,　a　three-dimensional　flow　model　of　an　air　film　in　an　aerostatic　spindle　is　established.　The　simulation　results　show　that　the　gas　flow　in　the　throttle　chamber　is　turbulent,　and　that　complex　vortices　are　formed.　Using　dynamic　grid　modeling　technology,　a　CFD　numerical　model　for　the　unsteady　calculation　of　the　spindle　is　established,　and　the　dynamic　characteristics　of　the　gas　film　are　obtained.　A　transient　dynamic　simulation　model　of　an　aerostatic　spindle　is　established,　and　the　effect　of　the　nonlinear　dynamic　characteristics　of　the　gas　film　on　the　spindle　displacement　response　is　investigated.　Subsequently,　a　surface　morphology　prediction　model　is　established.　Results　show　that　film　fluctuation　significantly　affects　the　dynamic　characteristics　of　the　spindle　and　subsequently　affects　the　generation　of　surface　ripples　on　the　workpiece.