The　marine　shallow　gas　hydrate　reservoirs　consist　mainly　of　non-diagenetic　hydrates,　characterized　by　shallow　burial,　weak　cementation,　loose　mineral　deposition,　and　fragility.　By　non-diagenetic,　we　mean　hydrates　that　have　not　undergone　significant　post-depositional　chemical　or　physical　alteration　processes,　unlike　diagenetic　hydrates,　which　form　through　chemical　and　structural　changes　in　sediments　after　their　deposition.　Conventional　extraction　methods　for　non-diagenetic　hydrates　often　lead　to　uncontrollable　and　unsafe　issues,　such　as　gas　collection　challenges　and　leakage　risks.　To　address　these,　this　paper　presents　a　gas-liquid-solid　multiphase　non-isothermal　transient　flow　model　incorporating　hydrate　phase　transitions　for　the　solid　fluidization　exploitation　method.　The　model　couples　multiphase　flow,　heat,　and　mass　transfer　in　the　wellbore　with　a　dynamic　decomposition　model　for　hydrate-bearing　particles.　An　optimization　method　for　key　parameters　in　hydrate　solid　fluidization　is　also　proposed.　The　results　show　that　the　critical　depth　of　hydrate　decomposition　increases　over　time,　with　a　rising　gas　phase　volume　fraction.　Increasing　mining　rate,　seawater　temperature,　and　salinity　accelerates　decomposition,　while　adjusting　wellhead　pressure　controls　the　decomposition　depth.　Higher　mining　rates,　seawater　temperature,　and　salinity　enhance　gas　production,　while　greater　wellhead　pressure　and　larger　wellbore　diameters　boost　solid　production.　These　findings　provide　key　insights　for　the　safe　and　efficient　transport　of　hydrate-bearing　particles　and　advancing　solid　fluidization　technology.　©　2024　Author(s).