For　a　direct　injection　natural　gas　engine,　the　fuel　jets　into　the　cylinder　in　cycles,　and　this　gas　pulsed　injection　process　causes　crucial　effects　on　the　combustion.　This　study　presents　an　experimental　investigation　on　the　methane　direct　injection.　An　optical　test　rig　is　designed　to　observe　the　high-pressure　methane　jet　into　a　constant-volume　bomb　(CVB),　and　a　numerical　model　is　built　to　analyze　the　gas　flow.　The　methane　jet　has　a　two-stage　feature.　The　gas　jet　characteristic　parameters　(the　tip　penetration,　penetration　speed,　jet　cone　cover　area)　change　rapidly　in　dynamic　stage　I,　and　become　stable　in　stable　stage　II.　The　dynamic　process　inside　the　nozzle　induces　this　two-stage　gas　jet　flow.　The　inner　methane　flow　experiences　a　time　delay　from　the　inlet　to　the　outlet,　and　the　gas　jet　undergoes　the　same　time　delay　to　maintain　stable.　Furthermore,　the　injection　pressure　has　great　effects　on　the　gas　jet.　As　the　injection　pressure　rises　high　enough,　the　gas　jet　saturation　behavior　occurs,　and　it　is　caused　by　inner　flow　saturation　of　Mach　number,　Reynolds　number　and　gas　velocity　inside　the　nozzle.　It　is　not　necessary　to　increase　injection　pressure　as　high　as　possible　for　improving　the　gas　jet　characteristics.