The invention discloses a movable LNG pressure-difference charging device and a use method of the movable LNG pressure-difference charging device and belongs to the technical field of LNG charging. The movable LNG pressure-difference charging device and the use method of the movable LNG pressure difference charging device are used for solving the problems that an existing LNG charging device is high in cost and inconvenient to operate. The movable LNG pressure-difference charging device comprises an LNG storage tank. The LNG storage tank comprises an outer container and two inner containers located inside the outer container. An interlayer between the outer container and the inner container is in vacuum and filled with a heat preservation material. The inner containers comprise a first inner container and a second inner container located on the right side of the first inner container. The first inner container is provided with a first liquid discharging pipe and a first gas feeding pipe communicating with the first liquid discharging pipe. The second inner container is provided with a second liquid discharging pipe and a second gas feeding pipe communicating with the second liquid discharging pipe. The movable LNG pressure-difference charging device has the advantages of being low in manufacturing cost and convenient to use.