Variable　valve　timing　(VVT)　and　Miller　cycle　are　advanced　technologies　employed　to　optimize　engine　performance　by　improving　airflow　exchange,　which　are　seldom　investigated　based　on　the　direct-injection　(DI)　hydrogen　engine.　The　objective　of　this　study　is　to　assess　the　effects　of　intake　valve　closing　(IVC)　and　exhaust　valve　opening　(EVO)　timing　on　the　gas　exchange　performance,　combustion,　and　emissions　of　a　DI　hydrogen　engine,　after　which　a　synergistic　control　strategy　of　IVC　and　EVO　timing　is　proposed.　This　work　is　conducted　under　wide-open　throttle　and　1500　rpm.　The　results　indicate　that　the　synergistic　control　of　IVC　and　EVO　timing　can　increase　volumetric　efficiency　by　more　than　40%,　enhance　gas　exchange　performance,　shorten　combustion　duration,　and　reduce　cyclic　variation,　resulting　in　approximately　43.15%　brake　thermal　efficiency.　Furthermore,　brake　mean　effective　pressure　can　be　increased　by　more　than　60%　and　NO　emissions　are　controlled　to　less　than　20　ppm　by　optimizing　valve　timings.&　COPY;　2023　Hydrogen　Energy　Publications　LLC.　Published　by　Elsevier　Ltd.　All　rights　reserved.