The　structure　chamber　of　rotary　engine　is　irregular　compared　with　traditional　reciprocating　engines.　Pure　n-butanol　rotary　engine　normally　encounters　partial　burning　and　even　misfire　at　idling　and　lean　conditions.　Comparatively,　hydrogen　supplement　can　ameliorate　performance　of　original　engine.　In　this　paper,　experimentation　of　a　rotary　engine　fueled　with　pure　n-butanol　and　hydrogen/n-butanol　blends　at　idling　and　different　excess　air　ratios　was　conducted.　Experimental　results　manifested　that　hydrogen　addition　effectively　decreased　the　engine　instability　and　fuel　energy　flow　rate.　To　be　specific,　fuel　energy　flow　rate　at　the　excess　air　ratio　of　1.05　was　reduced　from　23.63　MJ/h　to　21.26　MJ/h　when　3%　hydrogen　was　added.　Combustion　duration　was　lowered　after　introducing　hydrogen.　Maximum　chamber　temperature　was　heightened　after　hydrogen　addition.　HC　and　CO　emissions　were　reduced　when　3%　hydrogen　was　added.　NOx　emissions　were　reduced　when　the　mixture　was　leaned　out.