The　cooling　condition　of　the　landfalling　segment　of　the　submarine　cable　is　not　good,　so　it　is　of　prime　importance　to　consider　its　temperature　dependence.　To　investigate　the　cooling　performance　of　circulating　spraying　of　cold-water　pipe,　a　transient　thermal　path　model　and　a　three-dimensional　mathematical　model　of　multi-physical　coupling　fields　in　the　landfalling　segment　of　submarine　cable　were　established,　and　a　cooling　device　platform　was　built.　The　temperature　dependence　of　every　structural　floor　of　submarine　cable　under　two　models　was　discussed　and　contrasted,　and　the　cooling　performance　of　the　submarine　cable　cooling　device　was　studied.