The　motion　accuracy　of　hydrostatic　turntable　is　the　key　in　improving　the　machining　accuracy　of　heavy-duty　machine　tool.　However,　the　motion　accuracy　of　hydrostatic　turntable　depends　not　only　on　the　offset　load　but　also　on　the　rotating　speed　of　the　turntable　as　well　as　the　profile　errors　of　the　guide　rails.　In　this　paper,　a　simulation　model　is　developed　to　analyze　the　effect　of　guide　rail　profile　errors　on　the　motion　accuracy　of　hydrostatic　turntable.　The　reaction　forces　of　preload　thrust　bearing　and　hydrostatic　circular　oil　pads　are　obtained　based　on　the　Reynolds　equation　of　the　lubricant　film.　The　motion　equations　of　hydrostatic　turntable　are　derived　in　which　the　profile　errors　of　two　guide　rails　are　considered.　The　results　show　that　the　motion　accuracy　of　hydrostatic　turntable　can　be　affected　by　wavelength,　amplitude　of　profile　errors　and　speed,　and　offset　load　of　turntable.　Finally,　the　motion　accuracy　of　heavy-duty　hydrostatic　turntable　used　in　XCKA28105　type　turning　and　milling　composite　machine　tool　is　obtained　by　using　the　presented　method.　Comparing　with　the　experimental　results,　the　proposed　model　can　be　used　to　predict　the　machining　accuracy　caused　by　the　profile　errors　of　guide　rails　for　any　heavy-duty　hydrostatic　turntable.