Abstract: Gob-side entry retaining of Y-shape ventilation is a reliable method to control gas from coal seams. In this paper, downward through bed holes from gob-side entry retaining of Y-shape ventilation are used to continuously control gas from coal seams, and get the purpose of "one retained entry, multi-functions". The drilling method of boreholes is improved, and mud water is used to get cuttings out, and this greatly improves effect of removing cuttings and decreases defective rate of boreholes. The results show that the stress concentration zone should be avoided to decrease defective rate of boreholes; and in order to acquire high effect of gas drainage with downward through bed hole, the distance between crosshead and the rear end of borehole should be greater than 10 m.