The invention relates to the flow battery field and especially relates to a flow battery anode and cathode electrolyte migration control method. The method is characterized by using a Darcy law to construct a relationship between a volume migration rate of an anode and cathode electrolyte on two sides of a film and a pressure difference on two sides of the film; and then acquiring the relationshipbetween an anode and cathode porous medium pressure difference and a volume flow and viscosity of the electrolyte based on the Darcy law so that effective construction of the relationship among the volume flow of the anode and cathode electrolyte, the viscosity of the anode and cathode electrolyte and a volume migration rate of the electrolyte on the two sides of the film is realized. Based on that, a volume-flow ratio of the anode and cathode electrolyte is regulated and controlled through a viscosity value of the anode and cathode electrolyte so that migration of the electrolyte on the twosides of the film is effectively controlled. In the invention, a physicochemical property of the anode and cathode electrolyte and a rule of a porous medium are fully used, the migration rate of the electrolyte on the two sides of the film is effectively reduced under a condition that a complex design or equipment does not introduced, capacity attenuation of the flow battery is effectively controlled, and operation and maintenance cost of a flow battery system is greatly reduced.