The utility model provides a naval vessel sea water piping pipeline and naval vessel steel outer shell's insulating connecting device, includes: the interface flange of transition tube coupling and under -deck pipeline, transition tube coupling inner wall, lap joint flange, the lap joint flange position circle, sea chest export tube coupling flange, sea chest connects tube coupling and the outer surface insulating layer of transition tube coupling, sea chest export tube coupling diameter must want big than transition tube coupling diameter, and transition tube coupling material is the same with under -deck sea water piping material, the transition tube coupling passes through lap joint flange and adopts bolted connection with naval vessel sea chest export tube coupling flange, transition tube coupling surface needs cladding one deck insulating layer to lap joint flange is equipped with its position circle that down removes of restriction, distance above the transition tube coupling between lap joint flange and the under -deck sea water tube coupling interface flange is not less than 150mm. The utility model discloses utilize cuff technique, at the sleeve pipe surface cladding processing one deck insulating material at first including or of filling insulation material between two sleeve pipes, realize sealed and insulating target simultaneously.