In　order　to　solve　the　problems　of　the　high　cost　of　deep-sea　operation,　easy　damage　to　the　wellbore　structure　and　difficulty　in　long-term　stable　exploitation　in　the　current　marine　natural　gas　hydrate　trial　cases,　a　novel　marine　natural　gas　hydrate　self-entry　exploitation　device　and　method　were　proposed.　The　method　does　not　require　the　use　of　large　drilling　equipment,　and　the　new　device　carries　the　relevant　devices　into　the　reservoir　by　gravity　impact　and　then　performs　depressurization　exploitation,　which　can　be　reused　after　the　operation.　An　impact　penetration　model　and　a　depressurization　exploration　model　were　established　to　study　the　law　of　the　new　device　penetrating　into　the　seabed　reservoir　and　the　gas　production　characteristics　during　the　production　process.　The　results　show　that:　1)　the　depth　penetration　of　the　new　device　into　the　seabed　increases　with　the　increase　of　its　length　and　diameter,　up　to　a　maximum　of　370　m,　which　can　cover　the　burial　depth　of　most　natural　gas　hydrate　reservoirs;　2)　the　new　device　is　composed　of　a　prefabricated　steel　structure,　which　can　achieve　a　greater　pressure　reduction,　and　the　gas　production　efficiency　is　promoted　by　6　to　14　times　compared　with　the　traditional　wellbore　method.　©　2022,　Central　South　University　Press.　All　right　reserved.