The utility model provides a direct-current valve cooling system complete redundancy testing device, comprising an inner circulation main pump, a degassing tank, a plate heat exchanger and a simulated valve body which are connected into a main circulation loop through a pipeline. The direct-current valve cooling system complete redundancy testing device further comprises an ion exchanger and a precise filter which are connected into an auxiliary circulation loop through a pipeline. In addition, the direct-current valve cooling system complete redundancy testing device also comprises an original water pump, an original water tank and a water replenishing pump which are connected into a water replenishing loop. The water replenishing loop is connected with the ion exchanger, and the plate heat exchanger is cooled through an external cooling system. System composition of the direct-current valve cooling system complete redundancy testing device is identical to that of a valve cooling system, thereby being capable of simulating operating conditions of the valve cooling system in an all-dimensional mode, effectively replacing simulation, being convenient for controlling testing conditions, and shortening the test period.