In　order　to　further　improve　the　transmission　efficiency　of　the　cycloidal　pinwheel　reducer,　this　study　conducted　in-depth　research　on　the　influence　of　the　reducer　transmission　efficiency.　It　proposed　a　calculation　model　for　the　transmission　efficiency　of　the　cycloidal　pinwheel　reducer　that　takes　into　account　changes　in　design　parameters　and　working　condition　parameters　and　optimized　the　parameters.　Firstly,　considering　the　friction　force　and　meshing　backlash,　the　study　established　a　multi-tooth　load-bearing　contact　analysis　model　of　the　cycloid　pinwheel　transmission　mechanism,　and　calculate　the　meshing　force　and　load　distribution　pattern　of　the　cycloid　pinwheel　gear.　Then,　considering　the　engagement　loss,　output　loss,　bearing　loss,　lubrication　loss　and　sealing　loss,　this　paper　proposed　a　calculation　model　for　the　transmission　efficiency　of　the　cycloidal　pinwheel　reducer,　and　analyzed　the　influence　of　the　design　parameters　and　working　condition　parameters　on　the　transmission　efficiency　of　the　cycloidal　pinwheel　reducer.　Research　shows　that,　taking　frictional　stress　into　account,　rotation　speed,　load,　pin　tooth　pin　radius,　pin　tooth　distribution　circle　radius,　eccentricity,　and　pin　tooth　sleeve　radius　are　the　main　parameters　that　affect　transmission　efficiency,　followed　by　the　number　of　pin　teeth,　pin　distribution　circle　radius,　pin　radius　and　cycloid　tooth　width.　Finally,　the　optimal　parameter　solution　was　obtained　through　a　multi-objective　optimization　analysis　of　the　design　parameters　with　gear　strength,　gear　width,　tooth　profile　shape,　inter-tooth　clearance　and　load-bearing　capacity　as　the　parameter　optimization　range,　and　transmission　efficiency　and　volume　as　the　goals.　And　then　a　smaller　volume　and　more　efficient　cycloidal　pinwheel　reducer　was　obtained.　©　2024　South　China　University　of　Technology.　All　rights　reserved.