The　hydrogen-fueled　Wankel　rotary　engine　with　excellent　power　and　emission　characteristic　is　under　spotlight,　while　the　leakage　is　still　the　major　problem　for　Wankel　rotary　engine,　especially　the　leading　spark　plug　leakage.　The　peak　pressure　is　increased　from　3.34　MPa　to　3.52　MPa　and　the　indicated　thermal　efficiency　reaches　maximum　value　of　38.29%　when　the　moving　distance　of　leading　spark　plug　is　−6.5　mm,　and　the　mass　of　leakage　fresh　mixture　is　reduced　from　0.00311　g　to　0　g.　When　leading　spark　plug　is　moved　to　minor　axis,　the　flow　field　structure　of　working　chamber　is　enhanced.　However,　the　peak　pressure　and　indicated　thermal　efficiency　decrease　when　the　moving　distance　of　leading　spark　plug　exceeds　−6.5　mm.　The　excess　leakage　residual　gas　has　negative　effects　on　combustion.　The　optimum　moving　distance　of　leading　spark　plug　is　−6.5　mm　at　3000　rpm　with　λ　of　1.6.　©　2023　Hydrogen　Energy　Publications　LLC