The invention discloses a cold water circulating system of a vacuum oil purifier. The cold water circulating system of the vacuum oil purifier comprises a refrigerating unit, a cold water tank, a condensation pipe, a water storage tank and a vacuum pump. The refrigerating unit comprises an evaporator, a controller, a compressor, a filter and a refrigerating condenser. The refrigerating condenser is arranged at the center in the cold water tank, a heat preservation layer is arranged on the outside of the cold water tank, a water level gauge is arranged on one side of the cold water tank, a blow-down valve is arranged at the bottom of one side of the cold water tank, a water filling nozzle is arranged at one end of the top of the cold water tank, a temperature sensor is arranged at the other end of the top of the cold water tank, the other side of the cold water tank is provided with a water inlet and a water outlet, and the water outlet is provided with the filter. The water outlet is connected with the condensation pipe located in an oil and water separation condenser of the vacuum oil purifier, the tail end of the condensation pipe is connected with the water storage tank connected with the vacuum pump, the water discharging end of the water storage tank is connected with an air pump, and the water discharging end of the air pump is connected with the water feeding end of the cold water tank through a water pipe. Cold water circulating refrigerating is achieved, and energy is saved. The condensation effect of the vacuum oil purifier is effectively improved, and the use effect is improved.