Purpose　This　paper　aims　to　provide　thermal　elastohydrodynamic　lubrication　(TEHL)　contact　model　to　study　all　balls＇　lubrication　performance　of　the　ball　screw　when　the　multidirectional　load　is　applied.　Design/methodology/approach　A　new　TEHL　contact　model　combining　the　multidirectional　load　and　the　roughness　surface　texture　is　established　to　describe　fatigue　life　of　the　ball　screw.　Meanwhile,　the　authors　use　the　Reynolds　equation　to　study　the　lubrication　performance　of　the　ball　screw.　Findings　When　the　multidirectional　load　is　applied,　contact　load,　slide-roll　ratio　and　entrainment　velocity　of　all　balls　have　a　periodic　shape.　The　TEHL　performance　values　at　the　ball-screw　contact　points　including　contact　stress,　shear　stress,　minimum　film　thickness　and　temperature　rise　are　higher　than　that　at　the　ball-nut　contact　points.　The　TEHL　performance　values　increase　with　the　increase　of　root　mean　square　(RMS)　except　for　the　film　thickness.　In　addition,　the　radial　load　of　the　ball　screw　has　a　significant　effect　on　the　fatigue　life.　Originality/value　The　results　of　the　studies　demonstrate　the　new　TEHL　contact　model　that　provides　the　instructive　significance　to　analyze　the　fatigue　life　of　the　ball　screw　under　the　multidirectional　load.　Peer　review　The　peer　review　history　for　this　article　is　available　at:　https://publons.com/publon/10.1108/ILT-03-2020-0097/