Manufacturing　error　is　the　key　factor　affecting　the　transmission　accuracy　of　a　RV　reducer.　On　the　basis　of　the　gear　tooth　contact　analysis　method,　the　new　gear　tooth　contact　equations　for　a　two-stage　transmission　consisting　of　an　involute　gear　pair　and　a　cycloidal　pin　gear　pair　were　constructed　to　evaluate　the　influences　of　various　manufacturing　errors　on　the　transmission　error　of　the　RV　reducer　such　as　the　influences　of　the　tooth　profile　modification,　machining　error　and　assembly　error.　The　prediction　model　of　the　transmission　error　for　the　cycloidal　pin　wheel　mechanism　with　different　manufacturing　errors　was　obtained　to　calculate　the　sensitivities　of　various　manufacturing　errors　to　the　transmission　error.　Sensitivities　were　also　used　as　the　basis　for　the　selection　of　tolerance　levels　IT5　or　IT6.　According　to　different　tolerance　levels,　manufacturing　errors　were　expressed　as　Gaussian　random　numbers.　Furthermore,　through　the　processing　of　random　sampling　errors,　for　each　group　of　error　samples,　the　reliability　of　the　RV　reducer　without　interference　was　analyzed　and　the　distribution　of　transmission　errors　was　obtained.　The　results　show　that　the　position　error　of　the　pin　and　the　cumulative　pitch　error　of　the　cycloidal　gear　have　the　greatest　influence　on　the　transmission　error,　the　eccentricity　error　of　the　involute　gear　and　crank　shaft　has　little　influence,　and　the　influence　of　the　pin　radius　error　is　the　least.　Then,　the　machining　errors　with　lower　sensitivity　are　set　to　IT6　and　the　ones　with　higher　sensitivity　are　set　to　IT5.　The　transmission　error　accuracy　requirements　when　all　machining　errors　are　IT5　can　be　obtained,　the　reliability　is　98%,　and　the　machining　cost　is　lower.　It　can　be　utilized　as　the　basis　for　the　manufacturing　tolerance　level　selection　and　the　cost　control　of　RV　reducers.　©　2023　Chinese　Vibration　Engineering　Society.　All　rights　reserved.