Pervious concrete is used as the material for drainage structure in roads, buildings, and water facilities due to its excellent permeability. Existing devices for testing the permeability of pervious concrete do not consider the fluid leakage through the specimen-container interface induced by the large numbers of open pores on the surface of molded specimen. This may significantly affect the precision of the results. In this study, a new permeability test device for pervious concrete was developed and a modified permeability testing method is described. The modified method and currently used test methods were employed to measure the permeability of molded specimens with different porosities, graded aggregates, and admixtures. In order to calibrate the modified method, the permeabilites of the cored specimens were measured using the method and currently used test methods. The comparisons show that the permeabilities of the molded specimens measured using the modified method are lower than the two existing methods, and are approximate to the results of cored specimens. This indicates that for the molded specimens, the modified method can give better precision and more accuracy than the two existing methods.