The invention discloses a sample piece interior cavity water-through corrosion testing apparatus. The sample piece interior cavity water-through corrosion testing apparatus comprises a water tank, a plurality of corrosion testing sample piece fixing components and a circulating water pump, wherein the water tank is arranged on a base with multiple supporting legs and is used for containing circulating water and corrosion testing sample pieces; the corrosion testing sample piece fixing components are uniformly distributed in the water tank and are used for fixing multiple corrosion testing sample pieces; the circulating water pump is arranged on the base and positioned on one side of the water tank; the water outlet of the circulating water pump is communicated with the water tank through acirculating water pipe; the water inlet of the circulating water pump is communicated with the water tank through a water return pipe. The sample piece interior cavity water-through corrosion testingapparatus is capable of simulating water flow conditions in the interior cavity of the parts, and by utilizing continuous circulation of water, under the same condition, the interior cavity flow corrosion resistance of the sample pieces is compared, and both the testing efficiency and precision are high.