Ammonia　(NH3)　is　a　potential　alternative　fuel　for　internal　combustion　engines,　but　the　disadvantages　of　low　combustion　intensity　and　high　nitrogen　oxides　should　be　addressed　to　achieve　its　application.　For　NH3　mixture,　fuel　-rich　combustion　is　a　potential　method　to　reduce　NOx　emissions,　and　the　utilization　of　turbulent　jet　ignition　(TJI)　can　enhance　its　ignition　and　combustion.　Therefore,　a　strategy　of　using　TJI　with　assisted　oxygen　(O2)　injection　in　the　pre　-chamber　to　ignite　rich　NH3/air　mixtures　was　proposed　in　this　study.　Considering　the　lack　of　relevant　research,　a　fundamental　investigation　was　conducted　in　this　work.　The　results　indicate　that　the　provided　method　can　effectively　promote　the　combustion　of　NH3/air.　The　pre　-chamber　equivalence　ratio　has　no　significant　effect　on　the　jet　strength,　but　more　excess　injected　O2　enhances　the　ignition　performance　of　the　unburned　mixture　in　the　main　chamber.　The　increase　of　the　main　chamber　equivalence　ratio　and　the　decrease　of　the　orifice　diameter　will　result　in　a　higher　jet　velocity.　The　ignition　of　NH3/air　is　the　result　of　turbulence　competing　with　the　reactivity　of　the　mixture.　Therefore,　high　jet　velocity　leads　to　poor　ignition　performance　due　to　the　low　reactivity　of　NH3,　but　appropriate　turbulence　intensity　can　promote　rapid　combustion.