When　submarine　cable　line　fails　or　other　lines　need　load　transfer,　it　often　suffers　from　emergency　ampacity　that　exceeds　the　steady-state　ampacity.　The　layout　environment　of　the　submarine　cable　is　always　complex　and　changeable,　and　the　overload　capacity　of　the　submarine　cable　in　different　layout　environments　is　also　different.　Therefore,　it　is　necessary　to　analyze　the　overload　capacity　of　the　submarine　cable.　In　this　paper,　a　coupled　multi-physical　field　model　by　finite　element　method　is　established　for　AC　500　kV　XLPE　extra　high　voltage　submarine　cable　in　landing　section,　which　is　the　ampacity　bottleneck　section　of　the　whole　line.　The　overload　capacity　of　submarine　cable　in　two　typical　layout　environments　which　are　direct　buried　and　within　pipeline　is　analyzed.　The　results　show　that　the　overload　capacity　of　submarine　cable　in　the　direct　buried　environment　is　much　higher　than　that　in　the　pipeline　environment.　The　allowable　emergency　time　in　the　direct　buried　environment　is　2-3　times　that　of　the　pipeline　environment　under　the　same　condition.　In　the　two　typical　layout　environments,　when　the　emergency　current　are　2500　A　and　3500　A,　the　ratio　of　the　emergency　time　allowed　to　run　in　the　direct　buried　environment　to　that　in　the　pipeline　environment　is　about　5　times　under　the　same　initial　capacity.　The　proposed　model　can　provide　a　reference　for　dynamic　capacity　control　of　the　extra　high　voltage　submarine　cable.