The invention discloses a fuel heating system of a vessel. The fuel heating system comprises an oil bunker, heating coils and a steam system, wherein the two heating coils are arranged inside the oil bunker; the first heating coil is arranged close to a fuel suction hole of a lightering zone of the oil bunker, and is only used for heating fuel in the lightering zone; the second hating coil is arranged in the position outside the lightering zone of the oil bunker; and the steam system is connected with the two heating coils to independently control the two heating coils to operate. Compared with a traditional fuel heating system of the vessel, the fuel heating system of the vessel has the advantages that the preheating speed can be increased, and the energy conservation effect can be improved.