Abstract: In order to grasp the gas outflow pattern during the initial mining and releasing period of the first mining face under the Y-type ventilation method,the gas control work is taken in advance to prevent abnormal gas outflow and gas overlimit during the initial mining and releasing period. Taking the high level drilling holes in the first mining face of 1903 protective layer in Xintian Mine as the research object,we analyse the change curve of the concentration of drilling holes,the change of the concentration of sensors in the working face,and the corresponding relationship between the control distance of the drilling field and the degree of advancement of the mining face,and then put forward the rules of the fracture zone in the first mining face with the layer position between 15 ～ 26 m in the vertical three zones,the spacing of the high level drilling field of 20 m,and the rule of one cycle of pumping and extraction every seven days,and the rule of the initial collapse step distance of the direct roof during the period of the initial mining and initial releasing. During the period of initial mining and initial release,the first collapse step of the direct roof is 12. 2 m,and the first collapse step of the basic roof is 25 ～ 31 m. The results show that the high-level drill holes play an important role in the first mining and initial release of the first mining face of the 1903 protection layer.