Abstract: The present invention relates to a method for renmoving precipitate including: supplying anolyte stored in an anolyte tank to an anode inlet of a stuck through an anode inlet pipe; supplying the catholyte stored in a catholyte tank to a cathode inlet of the stack through an cathode inlet pipe; supplying the catholyte from the stack to the anolyte tank through an anode outlet pipe; and supplying the catholyte from the stack to the catholyte tank through an cathode outlet pipe, wherein in case of removing electrolyte precipitate in the cathode of the stack, the anolyte stored in the anolyte tank is supplied to the cathode inlet of the stack, the catholyte stored in the catholyte tank is supplied to the anode inlet of the stack, the anolyte discharged from a cathode outlet of the stack is supplied to the anolyte tank, and the catholyte discharged from an anode outlet of the stack is supplied to the catholyte tank.