Salt caverns with an inner container for storing electrical energy as a flow battery are provided. The salt caverns with an inner container for storing electrical energy as a flow battery comprises an air bag, a second pipeline and a first pipeline. The airbag is located in an underground salt cavern, the salt cavern is full of brine, and a liquid electrolyte is stored in the airbag. One end of the second pipeline is connected with the airbag while the other end thereof is located on the ground, and the second pipeline is used for filling the liquid electrolyte into the airbag. The first pipeline sleeves the second pipeline, one end of the first pipeline is connected with a shaft inlet of the salt cavern while the other end thereof is located on the ground, and the first pipeline is used for discharging the brine from the salt cavern.