Abstract: In order to solve the high gas emission quantity at 14221 mining face goaf of Xin'an Coal Mine, the unclear intrinsic relationship between the height, thickness and gas drainage of fissure zone, as well as the poor effect of drilling gas drainage, we use three different ways, such as calculating the empirical formula, computer simulation and field measurement, to identify the distribution of fractured zone height in goaf after mining and optimal area of drilling efficient drainage. Then analyzing experimental data, we present the alternate construction of two kinds of fractured zones with drilling gob gas drainage. By experiments, the gas concentration of single-hole is up to 48%, the average concentration of gas drainage in gob area is up to 36%, the pure gas drainage capacity is 3.8 m³/min. All these show that the gob gas drainage effect is improved significantly, and then effectively solves the existing problem of working face and protects the safety of mining face.