The　present　study　established　a　computational　fluid　dynamics　model　and　numerically　investigated　the　mixture　formation　and　combustion　processes　of　a　gasoline　rotary　engine　enriched　by　the　direct　injected　hydrogen　at　three　injection　positions.　It　is　found　that　the　special　flow　field　inside　rotary　engine　combustion　chamber　has　strong　interactions　with　the　hydrogen　jet-flow,　and　the　hydrogen　distribution　could　further　influence　the　charge　combustion.　At　the　end　stage　of　compression　stroke,　the　mainstream　field　whose　direction　same　to　rotor　movement　is　formed,　and　a　vortex　with　high　vorticity　existed　in　the　front　of　combustion　chamber.　With　the　influences　of　mainstream　field　and　vortex,　the　hydrogen　almost　fills　half　of　combustion　chamber　and　properly　rich　hydrogen　region　distribution　is　obtained　near　the　spark　plug　with　the　injection　position　close　to　the　spark　plug.　In　addition,　proper　equivalence　ratio　distribution　could　enhance　the　flame　propagation　and　mixtures　combustion　completeness　in　rear　region　of　combustion　chamber.　Compared　with　injection　position　far　away　from　the　spark　plug,　the　peak　in-cylinder　pressure　of　the　injection　position　close　to　the　spark　plug　increases　by　18.3%,　and　carbon　monoxide　emission　is　decreased　obviously,　but　nitrogen　monoxide　emission　increases　due　to　higher　in-cylinder　temperature.