Goaf water exited in No. 2 shaft No. 3 coal seam No. 8 mining area of southeast K8402、K8401 working face of No. 15 coal seam of No. 3 Mine in Yangquan Mining Industry, with hidden water hazard in K8402、K8401 working face. The distance between No. 15 and No. 3 coal seam reaches 80 m, waterhead pressure more than 1 MPa, the original water exploration and discharge sealing technology was improved to discharge No. 3 coal seam goaf water, with ZBQS-12/10 mine pneumatic double fluid grouting pump as driving and sodium silicate and cement rapid solidification principle, water seal casing and rock around were sealed to achieve the sealing goal. The sealing technology with 100% success rate since the experiment, gets remarkable economy and technology effect.