The utility model discloses a novel BOG reliquefaction device, a serial communication port, include: LNG storage tank, heat exchanger, heat sound refrigerator, pump, liquid nitrogen storage tank, the heat exchanger is provided with BOG entry, BOG export, inlet of liquid nitrogen, liquid nitrogen export, wherein the gaseous phase end of LNG storage tank is connected through the pipeline and the liquid phase end of LNG storage tank through the BOG entry linkage of pipeline with the heat exchanger, the BOG export of heat exchanger, and the inlet of liquid nitrogen of heat exchanger passes through the pipeline and is connected with the delivery side of pump end, and the liquid nitrogen export of heat exchanger is through the entry linkage of pipeline with heat sound refrigerator, liquid nitrogen storage tank's entry is respectively through pipeline and the export of heat sound refrigerator and the entry linkage of pump to pipeline connection is passed through with the entry of pump to the export of heat sound refrigerator. The utility model discloses reasonable in design not only, the liquid nitrogen can recycle, has reduced the BOG reliquefaction operation cost, adopts novel heat sound refrigerator moreover, has reduced equipment area.