This　paper　presented　an　experimental　study　about　the　idle　performance　of　a　rotary　engine　fueled　with　hydrogen　and　gasoline　blends.　The　idle　speed　was　reduced　from　original　2400　to　2300　and　2200　rpm,　and　hydrogen　energy　percentage　(beta(H2))　was　varied　from　0%　to　35.0%.　Test　results　showed　that　cyclic　variation　was　raised　with　the　decrease　of　idle　speed　whereas　reduced　with　the　increase　of　beta(H2).　Both　decreasing　idle　speed　and　increasing　beta(H2)　were　effective　on　reducing　engine　fuel　consumption.　Total　fuel　energy　flow　rate　was　effectively　dropped　from　22.4　MJ/h　under　＂2400　rpm　and　beta(H2)　=　0%＂　to　20.01　MJ/h　under　＂2200　rpm　and　beta(H2)　=　35.0%＂.　Combustion　duration　was　reduced　through　increasing)3H2.　HC　and　CO　emissions　were　dropped　with　the　increase　of　beta(H2),　but　increased　after　reducing　idle　speed.　CO2　emission　was　decreased　after　reducing　idle　speed　and　adding　hydrogen.　(C)　2017　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.