The　study　aims　to　numerically　investigate　the　combustion　and　emissions　formation　processes　in　a　spark-ignition　rotary　engine　fueled　with　hydrogen-gasoline　blends.　The　Renormalization　Group　k-e　turbulence　coupled　with　a　skeletal　primary　reference　fuel　mechanism　were　adopted　to　simulate　the　engine　working　process　under　0%,　2%　and　4%　hydrogen　volume　fractions　in　CONVERGE　software.　The　flow　field　variation　and　detailed　combustion　processes　were　analyzed　and　discussed.　Results　showed　that　a　mainstream　flow　field　along　with　the　rotor　movement　was　formed　during　the　compression　stroke　and　sustained　in　the　combustion　chamber　until　the　exhaust　valve　opening.　The　center　of　the　burned　zone　would　move　in　same　direction　with　the　mainstream　flow.　Meanwhile,　due　to　the　effect　of　the　mainstream　flow,　the　flame　propagation　in　direction　of　the　mainstream　flow　was　expedited.　While　the　flame　propagation　in　contrary　direction　was　retarded,　consequently,　the　unburned　mixtures　at　rear　region　of　combustion　chamber　suffered　incomplete　combustion.　The　distributions　of　nitric　oxide　and　carbon　monoxide　emissions　were　also　dominantly　affected　by　the　flow　field　in　the　combustion　chamber.　After　hydrogen　addition,　the　increased　OH,　H　and　O　radicals　concentrations　combined　with　the　intense　flow　flied　accelerated　the　combustion　process,　which　resulted　in　the　improvement　and　advancement　of　in-cylinder　pressure　and　temperature.　Compared　with　original　gasoline　case,　the　peak　in-cylinder　pressure　was　increased　by　9.1%　and　13.7%　with　2%　and　4%　hydrogen　blends,　respectively.　With　hydrogen　enrichment,　the　increased　in-cylinder　temperature　promoted　the　formation　of　nitric　oxide　emission.　Besides,　Carbon　monoxide　emission　was　decreased　with　the　increase　of　hydrogen　addition　fraction.