The invention discloses a sea bond structure for FPSO superstructure total segment during lightering. The sea bond structure comprises a lighter, a superstructure total section, a plurality of wall enclosing sea binding members, a plurality of longitudinal sea binding members, a plurality of transverse sea binding members and two outer wall sea binding members. The superstructure total section comprises an enclosing wall, an inner wall and an outer wall, wherein the enclosing wall comprises a larboard enclosing wall, a starboard enclosing wall, a bow enclosing wall and a stern enclosing wall;the inner wall comprises a first to a thirteenth longitudinal inner walls and a first to a ninth transverse inner walls; and one surface of the outer wall is provided with outer wall vertical stiffeners at intervals. The superstructure total section is hoisted on the deck of the lighter in a manner that the starboard enclosing wall is towards the bow of the lighter, and the stern enclosing wall istowards the starboard of the lighter, and a sixth transverse inner wall is superposed with the central line of the hull of the lighter. The enclosing sea binding members, the longitudinal sea bindingmembers, the transverse sea binding members and the outer wall sea binding members are of channel steel with the length equal to 500 mm. The sea bond structure has the advantages that materials are saved, the manpower, time and cost can be reduced and requirements on transportation safety can be met.