This　work　aims　to　improve　the　idle　performance　of　the　n-butanol　rotary　engine　by　blending　hydrogen　and　reducing　idle　speed.　Hydrogen　volume　percentage　(beta(H2))　changes　from　0　to　7.94%　and　the　idle　speed　decreases　from　2600　to　2400　rpm.　The　test　results　show　that　the　engine　can　achieve　better　stability　and　economy　due　to　the　coupling　effect　of　mixing　hydrogen　and　reducing　the　idling.　The　total　fuel　flow　rate　reduces　from　24.57　MJ/h　at　2600　rpm　when　pure　n-butanol　is　fueled　to　19.35　MJ/h　at　2400　rpm　when　beta(H2)　equals　to　7.94%.　The　period　of　flame　development　and　propagation　are　observably　decreased　by　blending　hydrogen　even　if　reducing　idle　speed　has　a　few　negative　effects.　Hydrogen　enrichment　is　an　effective　way　to　reduce　the　emissions　of　CO　and　HC.　Besides,　the　negative　effects　of　reducing　idle　speed　on　HC　and　CO　emissions　are　decreased　to　a　negligible　level　when　beta(H2)　passes　about　7%.　Besides,　NOx　emission　is　maintained　at　an　extremely　low　value　in　the　testing　range.　Also,　enrichment　hydrogen　can　compensate　for　the　negative　effects　on　combustion　and　emissions　of　reducing　idle　speed.