This　paper　presents　a　Large　Eddy　Simulation　(LES)　study　investigating　jet　flame　ignition　characteristics　to　achieve　stable　ammonia　combustion　for　novel　applications　in　gaseous　ammonia/hydrogen-fueled　engines　with　an　active　prechamber.　The　study　investigated　three　cases　with　initial　global　equivalence　ratios　of　0.6,　0.8,　and　1.0.　Two　main　ignition　modes　were　proposed,　and　five　stages　of　coupled　flame　propagation　processes　were　identified.　The　oscillation　of　supersonic　hydrogen　jet　flame　was　investigated.　The　modes　of　flame-vortex　interaction　including　vortex　ring　formation,　along　with　the　mechanism　of　highly　reactive　zone　formation,　were　proposed.　The　effects　of　reactivity　and　turbulence　transition　on　piloted　ammonia　flame　were　investigated　to　attain　stable　ammonia　combustion　and　achieve　a　high　heat　release　rate.　The　results　showed　that　oscillations　in　the　jet　flame　were　strengthened　at　low　global　equivalence　ratios　with　high　hydrogen　mass　ratios.　Enhancing　propagation　of　initial　and　secondary　vortex　rings　broadened　highly　reactive　zones.　Vorticity　dissipated　more　rapidly　at　low　equivalence　ratios,　leading　to　a　stratified　structure　and　enhanced　piloted　spherical　flame.　The　Unsteady　Flamelet　Ignition　Prediction　(UFIP)　sub-model　of　combustion　was　verified　for　the　piloted　ammonia　flame,　enabling　a　more　comprehensive　discussion　of　flame　propagation　tendencies.