A fuel cell hybrid power system for a vessel is disclosed. The fuel cell hybrid power system for a vessel according to the present invention comprises: a storage tank formed in a hull and in which liquefied natural gas (LNG) is stored; a fuel cell unit formed in the hull for generating high-temperature gas by an electrochemical reaction of supplied hydrocarbon materials; a steam generating unit generating steam by using high-temperature gas discharged from the fuel cell unit as a medium; and a steam gas supplying unit for supplying boil-off gas generated in the storage tank to at least one of the fuel cell unit and the steam generating unit.
