Abstract: Surrounding rock cracks of 4^＃ coal seam and sandstone contain plenty of water, which results in lots of water remained in downward drillings bottom and low rate of gas extraction. We analyze factors that affect gas extraction effect. Based on the principle of sealing compressor drainage, we propose blocking grouting, protecting holes, two plugging and one injection hole sealing method and drainage technology to implement the efficient extraction of down hole. Comparing gas extraction effect of drilling with related technical measures and drilling without technical measures in engineering practice, the results show that average one-hole concentration in measured drilling field is 4 times higher than that without taking measures. Also, average one-hole flow in measured drilling field is 2 times greater than that without taking measures. The construction techniques can enhance the effect of gas extraction largely.