The　new　type　of　nutation　reducer　with　double　circular-arc　bevel　gears　as　the　core　is　characterized　by　advantages　such　as　high　load-bearing　capacity,　large　transmission　ratio,　and　simple　structure.　The　existing　research　focuses　on　the　machining　methods　of　gears　and　the　analysis　of　tooth　contact.　This　article　first　time　establishes　an　elastohydrodynamic　mixed　lubrication　model　for　nutation　double　circular-arc　bevel　gear.　The　model＇s　accuracy　is　verified　by　comparing　it　with　existing　test　results.　On　this　basis,　combined　with　the　finite　element　method　and　tooth　contact　analysis,　the　meshing　characteristics,　tooth　contact　characteristics,　and　lubrication　characteristics　of　the　double　circular-arc　bevel　gear　tooth　surface　are　analyzed.　The　results　show　that　the　entrainment　velocity　at　the　contact　point　of　the　tooth　surface　during　transmission　is　much　higher　than　the　sliding　velocity.　Consequently,　the　meshing　motion　is　close　to　pure　rolling.　In　constant-speed　transmission,　the　oil　film　thickness　at　the　engaging-in　and　exit　points　near　the　edge　of　the　tooth　surface　is　smaller　than　that　at　other　meshing　points　on　the　tooth　surface.　This　phenomenon　can　easily　lead　to　mixed　lubrication　and　lubrication　failure,　as　well　as　tooth　surface　wear.　During　deceleration,　i.e.,　when　the　speed　drops　to　50 r/min,　the　oil　film　thickness　approaches　zero,　indicating　that　the　gear　has　entered　a　mixed　lubrication　state.　The　proposed　model　can　be　used　for　lubrication　analysis　and　improving　transmission　accuracy　of　nutation　double　circular-arc　bevel　gears.　©　IMechE　2024.