The invention provides a device for testing the air permeability of a graphite material. The device comprises an air storage tank, a pressure stabilizing tank, a pressure reducing filter, a flow meter, a testing tank, a tee joint, an exhaust pipe and a differential pressure gauge, the testing tank comprises a lower pipe, an upper pipe, a lower annular rubber pad, a radial sealing ring, an upper annular rubber pad, a graphite material sample and a sealing ring; the pressure difference exists between the two sides of the sample in the thickness direction; gas passing through a sample, the differential pressure of the two sides of the sample in the thickness direction is displayed by the differential pressure gauge, the pressure and the flow of gas flowing through the sample are displayed bythe flow meter, and then the air permeability of the graphite material is calculated according to a differential pressure method, so that the air permeability of the graphite material with high density and very small air permeability is detected, and the precision and the accuracy are relatively high.