Abstract: For the difficulty of gas extraction in the low permeability coal seam, a new technology of directional hydraulic blasting by preseting guide seams is proposed. Using the common orientation of guide seams in blasting holes and observe holes around the blasting holes, the directional hydraulic blasting is fulfilled in the blasting holes. Coal body between blasting holes and the observe holes is penetrated, so as to relieve the seam pressure and increase permeability. The directional hydraulic blasting mechanism is proposed and analyzed. The technological procedures of the directional hydraulic blasting by preseting guide seams is expounded. The field tests show that compared with the ordinary hydraulic blasting, gas drainage influence radius using the directional hydraulic blasting by preseting guide seam is over 7 m. The gas drainage of blasting hole in unit time is about 1.467 times of the original. The efficiency of gas extraction is significantly improved.