The invention discloses a method and a device for realizing low-temperature quick start of a flow cell system and the flow cell system. The method comprises the following steps: receiving a power scheduling instruction comprising appointed time of input or output power of the flow cell system; obtaining a time interval between the start time and the appointed time of the flow cell system; when the time interval is greater than or equal to a preset time interval, enabling electrolyte in an anode storage tank to directly return to the anode storage tank through an anode electrolyte outlet, a pipeline and an anode electrolyte inlet, and enabling electrolyte in a cathode storage tank to directly return to the cathode storage tank through a cathode electrolyte outlet, a pipeline and a cathode electrolyte inlet; heating the electrolyte in the anode storage tank and the electrolyte in the cathode storage tank. The method realizes that electrolyte temperatures in the anode storage tank and the cathode storage tank are quickly and efficiently enabled to reach proper temperatures, so that the running time of the flow cell system at a start-up initial stage is shortened and the running efficiency of the flow cell system is improved.