The invention discloses a supercharging oil extraction method and a device thereof through guiding high-pressure gas-liquid jet close to a deepwater oil field mud line well opening. The device comprises a high-pressure pipeline and a flow-guiding supercharging device, wherein one opening of the high-pressure pipeline is communicated with an inlet of the flow-guiding supercharging device; the other inlet of the flow-guiding supercharging device is communicated with a fluid pipeline I; an outlet of the flow-guiding supercharging device is connected with an external transmission pipeline; and the high-pressure pipeline, the fluid pipeline and the external transmission pipeline are all provided with valves. With the adoption of the device, one stage supercharging can be realized through the manner that high pressure gas well fluid pressure energy is directly transformed into seabed low pressure oil well supercharging power under a condition that the external transmission pressure of IPSO (international programme on the state of the ocean) is definite; secondary supercharging is realized through the manner that pressure reduction from a mud line well opening to FPSO (floating production storage and offloading) can be effectively reduced by the introduced high pressure gas, so that the oil pressure of a seabed low pressure oil well is greatly lowered, the blowing period is prolonged, and the blowing recovery efficiency is improved.