The variation and calculation method of grain resistance under different conditions of transverse and vertical ventilation was researched with the square-bin stored 180t corn as test-bin. The transverse and vertical ventilation equipment was designed and installed in the test-bin respectively. The grain resistance was got under different ventilation modes by experiments. The results showed that the unit grain resistance of transverse ventilation was 1time lower than that of vertical ventilation and the anisotropy in stored corn was significant. The formula of grain resistance under the transverse ventilation was firstly obtained by experiments. Likewise, one under the vertical ventilation was also got. The formulas indicated that the character of stored corn resistance was accord with the mechanics laws of porous media. Thus the grain resistance was calculated either accurately by Hunter binomial formula of porous media or approximately by Shedd power function formula.