This　study　focuses　on　a　four-cylinder,　four-stroke　hydrogen　engine　equipped　with　a　passive　pre-chamber　(PC).　The　effects　of　excess　air　ratio　(lambda)　on　the　performance　of　the　turbulent　jet　ignition　(TJI)　hydrogen　engine　are　investigated　through　experimental　and　numerical　simulations.　The　hydrogen　engine　operates　at　1600　rpm　with　an　intake　manifold　pressure　of　70　kPa.　The　results　show　that　lambda　values　significantly　influence　the　internal　flow　field,　energy　distribution,　and　flame　development　in　the　PC,　affecting　the　combustion　in　the　main　chamber　(MC).　The　experiment　found　that　as　lambda　decreases,　the　BMEP　and　BTE　gradually　increase.　Due　to　the　influence　of　jet　and　multi-point　ignition,　the　heat　transfer　loss　in　lean　combustion　is　also　relatively　high.　The　jet　oscillation　caused　by　the　TJI　hydrogen　engine　has　high　controllability　and　low　destructiveness,　and　lambda　is　one　of　the　main　factors　controlling　the　jet　oscillation.　The　influence　of　spark　timing　(ST)　on　engine　performance　is　explored　through　experiments.　The　results　show　that　as　lambda　increases,　the　sensitivity　of　BMEP　to　ST　gradually　decreases.　With　the　delay　of　ST,　BTE　increased　first　and　then　decreased.　However,　the　cyclic　variation　is　less　affected　by　ST.　For　the　TJI　hydrogen　engine,　an　appropriate　delay　in　ST　under　the　close　stoichiometric　ratio　condition　can　not　only　ensure　power　output　and　combustion　stability　but　also　reduce　emissions.