The invention relates to a sealed liquid storage tank with an elastic inner container compensation device. The sealed liquid storage tank with the elastic inner container compensation device comprises a sealed liquid storage tank body. The top of the sealed liquid storage tank body is provided with a liquid inlet and a liquid inlet electromagnetic valve. The bottom of the sealed liquid storage tank body is provided with a liquid outlet and a liquid outlet electromagnetic valve. An elastic inner container is arranged in the sealed liquid storage tank body. A blow-down pipe, an airflow balance pipe and an electric contact pressure gauge are further arranged on the top of the sealed liquid storage tank body. The head end of the airflow balance pipe is connected with an elastic inner container vent of the elastic inner container, the tail end of the airflow balance pipe is connected with an air compressor through a three-way straight pipe electromagnetic valve, and the airflow balance pipe is further provided with a three-way bypass electromagnetic valve. The sealed liquid storage tank body is further provided with an electric contact liquid level meter. The sealed liquid storage tank further comprises a control module used for automatically controlling the electromagnetic valves. The invention further relates to a using method of the sealed liquid storage tank with the elastic inner container compensation device. Liquid in the sealed liquid storage tank body is kept isolated from outside air and prevented from being affected with damp, oxidized and polluted, and the effect that the liquid can be stored safely and reliably for a long time is guaranteed.