The utility model discloses an adopt novel mode to arrange LNG supply of fuel system of buffer tank, include: gas storage system and steady voltage gas supply system to pass through the tube couplingbetween gas storage system and the steady voltage gas supply system, gas storage system includes: place, heated gas ization system device, LNG pipeline are connected to storage tank, storage tank, theone end and the heated gas ization system device of storage tank all lie in the storage tank and are connected the place to through the LNG tube coupling, the steady voltage gas supply system include: buffer tank, GVU case, engine, gas -phase pipe way, the buffer tank is located GVU incasement portion to the buffer tank is connected with GVU case, heated gas ization system device respectively through the gas -phase pipe way, the GVU case passes through the gas -phase pipe way and is connected with the engine. With the buffer tank setting at the GVU incasement for the buffer tank shortens to the distance between the engine, and the engine is given to the natural gas that can provide pressure stability, thereby satisfies the demand that engine work load changes, has improved engine gas supply system's stability and reliability greatly.