The invention relates to a device for testing whitening of a cement-based material by adopting a hydrostatic pressure method. The device comprises a whitening test container, a water storage tank anda U-shaped hydrostatic pressure output hose, the water storage tank is arranged at the lower portion of the whitening test container, the hydrostatic pressure output hose is connected with the lower portion of the water storage tank, a cement-based material test block is placed in the whitening test container, water is injected into the water storage tank through the hydrostatic pressure output hose, a sealing layer is arranged between the whitening test container and the water storage tank, the sealing layer is provided with an open hole matching with the lower end of the cement-based material test block in shape, and the bottom portion of the cement-based material test block is in contact with the water in the water storage tank through the open hole. Compared to the prior art, the device is simple and reasonable in structure, is capable of accurately testing the whitening performance of the cement-based material test block, and is high in working efficiency and convenient to operate.