The utility model discloses a sodium thiosulfate crystallizing tank. The sodium thiosulfate crystallizing tank comprises a tank body, wherein an S-shaped cooling circulation water pipeline I and an S-shaped cooling circulation water pipeline II parallel to each other are arranged in the tank body; a water inlet valve I is arranged at a water inlet of the S-shaped cooling circulation water pipeline I; a water inlet valve II is arranged at a water inlet of the S-shaped cooling circulation water pipeline II. The sodium thiosulfate crystallizing tank has the advantages that the two groups of cooling circulation water pipelines are arranged in the tank body and respectively provided with the water inlet valves, so that the two groups of cooling circulation water pipelines are separately controlled and used for cooling a material solution; when severe heat exchange is generated on the S-shaped cooling circulation water pipeline I, the scab of the sodium thiosulfate material solution on the S-shaped cooling circulation water pipeline I is relatively thick; when the heat exchange effect is poor, the S-shaped cooling circulation water pipeline II is opened, the cooling process of the sodium thiosulfate material solution is accelerated and the crystallizing period is shortened, so that the single-tank capacity of products is improved.