The invention relates to the technical field of electric vehicles, in particular to a circulating device of an electric vehicle battery thermal management system and a control method of the circulating device. The circulating device comprises a main water tank, a motor water pump, an auxiliary water tank, a water level sensor, a solenoid valve I, a pipeline heater, a three-way valve, a lithium battery pack, a temperature sensor, a controller, a solenoid valve II and a heat dissipation tank, wherein the motor water pump, the temperature sensor, the controller, the water level sensor, the solenoid valve I and the solenoid valve II are connected with one another via conducting wires to form a control system; the main water tank, the auxiliary water tank, the solenoid valve I, the solenoid valve II, the heat dissipation tank, the three-way valve and the lithium battery pack are connected with one another via pipelines to form a heat dissipation loop; the main water tank, the auxiliary water tank, the solenoid valve I, the pipeline heater, the three-way valve and the lithium battery pack are connected with one another via pipelines to form a heating loop. Through the three different circulating modes, a battery can work in a stable, efficient and safe temperature range, so that the excessive heat loss is greatly reduced to achieve the purpose of saving energy, and the service life of the battery is prolonged.