In order to calculate the resistance of grain heap when ventilated with vertical ventilation system, an experiment was carried out in an experimental store house with 180t wheat to detect the resistance in grain heap during vertical bidirectional ventilation with different direction and superficial gas velocity. The results indicated that during vertical ventilation, the resistance existed both on and inside the grain heap.The total resistance of grain heap was the sum of the facial resistance and the interior resistances. There was no strictly proportional relationship between the total resistance and the height of the pile. Comparing the upwards vertical ventilation with the downwards vertical ventilation, there was obvious difference between facial resistance and interior resistance, the higher the airflow, the larger the difference, which illuminated that the grain heap is anisotropic.