Fuel supply system of dual-fuel direct injection system engine

The invention discloses a fuel supply system of a dual-fuel direct injection system engine. According to the fuel supply system of the dual-fuel direct injection system, gas fuel is stored in a liquefied gas bottle in a liquid state, liquid fuel is stored in an oil tank, the liquid fuel in the oil tank is conveyed to a dual-metering oil supply pump, and the dual-metering oil supply pump pressurizes the liquid fuel and then conveys the liquid fuel to an oil rail and an adapter body. The oil rail provides a high-pressure oil source for the dual-fuel injector, and the switching body provides a high-pressure oil source for the low-temperature pump. A low-temperature pump is arranged in the liquefied gas bottle, liquefied gas fuel is pressurized by the low-temperature pump and vaporized into gas, then the gas fuel is conveyed to the buffer tank, the gas in the buffer tank is adjusted by the pressure adjusting valve and then conveyed into the gas rail, and the gas rail provides a high-pressure gas fuel source for t