Lean　combustion　is　a　promising　method　for　getting　ameliorate　engine　performance.　However,　due　to　the　small　flammability　of　gasoline　and　elongated　combustion　chamber　of　rotary　engine,　gasoline　rotary　engine　tends　to　encounter　partial　burning　and　even　misfire　when　mixtures　are　dilute.　Hydrogen　(H-2)　occupies　many　advantages　that　may　remit　the　aforementioned　problems.　For　this　motivation,　a　rotary　engine　installed　gasoline-H-2　port-injection　system　was　developed　to　explore　the　performance　of　rotary　engine　fueled　with　H-2-gasoline　blends　at　part　load　and　lean　conditions.　A　speed　of　4500　rpm,　a　manifold　absolute　pressure　(MAP)　of　35　kPa　and　a　spark　advance　of　25　degrees　CA　were　adopted　for　this　research.　Hydrogen　volume　fraction　(ant)　was　kept　at　0,　3%　and　6%,　respectively.　Excess　air　ratio　(lambda)　was　gradually　enlarged　from　1.00　with　a　step　of　0.05.　For　a　given　lambda,　when　axe　was　increased,　the　results　were　showed　subsequently.　Peak　chamber　pressure　was　increased　and　its　corresponding　crank　angle　was　advanced.　Brake　mean　effective　pressure,　peak　combustion　temperature　and　brake　thermal　efficiency　were　simultaneously　increased.　Flame　development　and　propagation　periods,　cooling　loss　and　cyclic　variation　were　reduced.　HC　and　CO　emissions　were　lessened　whereas　NOx　emissions　were　heightened　due　to　the　raised　combustion　temperature.