The　attractiveness　of　oxygen-enriched　combustion　advantages　are　making　a　comeback　in　the　implementation　of　the　rotary　engine　concept.　In　this　connection,　a　numerical　investigation　on　influences　of　intake　oxygen　enrichment　combined　with　excess　air　ratio　on　combustion　behavior　of　the　rotary　engine　needs　to　be　clarified.　A　three-dimensional　computational　fluid　dynamics　simulations　coupling　with　chemical　kinetic　mechanisms　was　performed　in　this　study,　and　the　numerical　results　had　been　validated　with　existing　experimental　data.　The　species　evolution,　combustion　characteristics,　and　pollutant　formation　were　monitored　to　assess　the　oxygen-enriched　combustion　of　the　rotary　engine.　Results　showed　that　there　was　a　significant　influence　of　intake　oxygen　enrichment　for　improving　flame　development　and　burned　volume　due　to　the　reasonable　species　concentration　and　intense　turbulence　intensity.　Increasing　oxygen　enrichment　led　to　the　enhanced　peak　pressure　and　advanced　corresponding　position,　resulted　in　a　rapid　combustion　period　for　improving　heat-release　efficiency　and　combustion　efficiency,　meanwhile　made　a　higher　indicated　mean　effective　pressure　at　the　price　of　a　smaller　increment　of　nitrogen　oxide　formation.　The　substantial　reductions　of　carbon　monoxide,　unburned　hydrocarbon,　and　soot　were　recorded,　which　is　attributed　to　the　higher-oxygen　mixture　with　suitable　lean　operations.　Considering　combustion　characteristics　and　emissions　performance,　the　operation　of　intake　oxygen　volume　of　30%　accompanying　the　excess　air　ratio　of　1.1　is　the　best　choice　for　the　engine　used　in　the　current　study.