The　flammability　limits　of　the　hydrogen-oxygen　mixture　are　extremely　wide,　and　the　ignition　energy　is　low.　Due　to　its　excellent　combustion　properties,　the　hydrogen-oxygen　mixture　can　be　used　as　fuel　in　internal　combustion　engines　(ICEs).　However,　the　combustion　of　hydrogen-oxygen　mixture　is　too　intense,　which　results　in　limited　research　on　its　application　in　ICEs　and　is　limited　to　low-temperature　conditions　in　aerospace.　This　research　aims　to　numerically　discuss　the　coupling　effects　of　equivalence　ratio　and　ignition　timing　on　the　port　fuel　injection　hydrogen-oxygen　ICE　under　the　low-temperature　intake　condition.　The　three-dimensional　geometric　model　of　a　single-cylinder　ICE　was　established　using　the　CONVERGE　software　and　validated　against　the　mean　in-cylinder　pressure　and　reaction　mechanism.　The　results　indicate　that　adjusting　equivalence　ratio　and　ignition　timing　operating　parameters　is　beneficial　for　controlling　the　temperature　and　pressure　in　the　cylinder　within　a　reasonable　range　during　the　total　combustion　process.　In　general,　under　the　low-temperature　intake　condition,　adopting　a　high　equivalence　ratio　and　optimal　ignition　timing　strategy　improve　the　combustion　process　and　power　performance　of　the　port　fuel　injection　hydrogen-oxygen　ICE.　©　2024,　The　Author(s).