The　comparative　study　on　performance　of　the　hydrogen/gasoline　and　hydrogen/n-butanol　rotary　engines　was　conducted　in　the　present　paper.　Considering　the　stable　operation　of　the　engine,　for　both　hydrogen/gasoline　case　and　hydrogen/n-butanol　case,　the　operating　conditions　were　set　at:　4000　rpm　(engine　speed),　35　kPa　(intake　pressure)　and　30　degrees　CA　BTDC　(spark　timing).　The　total　excess　air　ratio　of　mixture　was　maintained　at　1.0　through　all　the　tests.　The　testing　results　displayed　that　hydrogen　enrichment　improved　performance　of　both　gasoline　and　n-butanol　rotary　engines.　To　be　more　specific,　brake　thermal　efficiency　was　increased,　flame　development　and　propagation　periods　were　shortened,　the　coefficient　of　variation　in　flame　propagation　period　was　decreased,　and　the　emissions　of　HC　and　CO　were　decreased.　NOx　emissions　were　mildly　increased　after　hydrogen　addition.　Besides,　hydrogen/n-butanol　rotary　engine　possessed　the　similar　performance　to　hydrogen/gasoline　rotary　engine.　(C)　2018　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.