The　gas　spindle　is　a　key　component　in　wafer　thinning　equipment.　The　performance　of　the　gas　spindle　directly　affects　the　wafer　processing　quality.　By　establishing　the　mathematical　model　of　the　gas　spindle　thrust　bearing　flow　field,　the　gas　flow　process　in　the　orifice　and　gas　film　is　studied,　and　the　bearing　capacity　distribution　of　the　thrust　bearing　is　obtained.　The　variation　of　the　bearing　characteristics　of　the　thrust　bearing　with　the　thickness　of　the　gas　film　is　analyzed　in　detail.　Between　1µm　~　11µm,　the　bearing　capacity　declines　gently,　and　the　capacity　changes　by　only　2%.　Between　12µm　and　30µm,　the　bearing　capacity　has　a　significant　downward　trend,　from　6800N　to　1800N,　a　decrease　of　73%.　After　31µm,　the　change　in　bearing　capacity　is　attributed　to　a　gradual　change.　Before　18µm,　the　stiffness　value　increases　with　the　increase　of　the　thickness　of　the　gas　film,　and　increases　rapidly.　The　maximum　stiffness　value　appears　at　18µm,　which　is　376N/µm.　In　addition,　compared　with　the　increasing　trend　of　stiffness　value,　the　downward　trend　is　relatively　gentle.　Through　the　above　research,　it　provides　a　theoretical　reference　for　the　development　of　thinning　equipment.　©　2020　IEEE.