The　hydrostatic　spindle　system　is　the　main　internal　heat　source　of　the　machine　tool,　thus　it　is　very　significant　to　study　the　thermal　behaviors　of　the　hydrostatic　spindle　system.　The　purpose　of　this　study　is　to　investigate　the　effect　of　viscosity-temperature　effect　of　lubricant　on　the　temperature　fields　of　hydrostatic　bearing　oil　film　and　spindle　thermal　deformation.　To　study　the　effect　of　temperature　rise　of　hydrostatic　bearing　oil　film　on　the　hydrostatic　spindle　and　bearing　bush,　empirical　equations,　CFD,　and　experimental　methods　are　used　in　this　paper.　Firstly,　the　temperature　rise　of　hydrostatic　bearing　is　obtained　by　the　theoretical　calculation　method.　Secondly,　based　on　the　CFD,　the　temperature　field　of　lubricating　oil　film　is　compared　and　analyzed　with　consideration　of　viscous　temperature　effect　and　constant　value　of　viscosity.　Based　on　the　fluid-thermal-solid　coupling　method,　the　thermal　deformation　of　the　spindle　is　analyzed.　Finally,　the　experimental　platform　of　the　hydrostatic　spindle　is　built　and　the　accuracy　of　the　simulation　results　was　verified.　The　study　shows　that　when　the　viscosity-temperature　effect　is　considered,　the　values　of　oil　film　temperature　rise　and　spindle　thermal　deformation　are　closer　to　the　experimental　values,　and　the　error　rates　of　bearing　temperature　and　spindle　thermal　deformation　are　smaller　than　those　when　the　viscosity　is　fixed.　©　2023,　The　Author(s),　under　exclusive　licence　to　The　Brazilian　Society　of　Mechanical　Sciences　and　Engineering.