Fortheproblemofgasrarefiedeffectinsidetheaerostaticbearinginconditionofmicroclearance,theReynoldsequationsuitableforcompressiblegasintherarefiedeffectwasdeducedthroughintroducingflowfactoroftherarefiedeffecttotheReynoldsequation.TheReynoldsequationwasdissociatedbyusingthefiniteelementmethod,pressuredistributioninthebearingundertherarefiedeffectwereanalyzedbythesoftwareMATLAB,theinfluenceruleofrarefiedeffecttothebearingperformancecapacityandstiffnesswasstudied,whichwasverifiedbyexperimentindirectly.Theresultsshowedthatthestiffnessofbearinginconditionofconsideringtheflowfactorwasclosetothestiffnesstestedbyexperimentwhenthegasclearancewas8~10μm.Thevalueofanalysiswas20%lessthantheexperiment,whichprovidedatheoreticalbasistotheresearchoftheperformanceofbearingsinmicro-scale.