The invention discloses a temperature adjusting method of an accumulator of a pure electric vehicle or an accumulator of a hybrid electric vehicle. The temperature adjusting method comprises the following steps of detecting the temperature of the accumulator; judging whether the temperature of the accumulator achieves a tolerance threshold or not; and if yes, after a vehicle-mounted refrigerating system is started, branching a part of or all of refrigerants in a first refrigerating circuit to a second refrigerating circuit to allow the accumulator to be cooled. The vehicle-mounted refrigerating system comprises the first refrigerating circuit and the second refrigerating circuit, wherein the first refrigerating circuit is used for refrigerating a driving cab; and the second refrigerating circuit is used for cooling the accumulator. According to the technical scheme of the temperature adjusting method disclosed by the invention, a conventional refrigerating technology in the driving cab of the vehicle can be utilized; and when the accumulator needs cooling, the refrigerants are branched for cooling the accumulator, so that the cost is saved, and the cooling effect of the accumulator is guaranteed.