Abstract: To solve the problem of the gas consistence exceeding limit at the upper corner of working face, the distribution laws and charicteristics of overburden strata "three zones" during mining are studied by physical simulation experiment aiming at the situation of (4-5)04 working face in Liuhuanggou Coal Mine. High level borehole is designed by the experiment result for drainage gas at upper corner of working face and its drainage effect is observed and analyzed in real time. The results show that caving degree is about 71°and there are a lot of fractures in overburden strata. The height of caving zone and fractured zone are 25 m to 26.8 m and 109.2 m to 110 m. Its first weighting interval and average periodic weighting distance is 36 m and 16.6 m. The width of cracked zone is 40 m near cut hole. It is about 30 m near return airway and airflow airway. It is from 20 m to 40 m near working face during mining. The drainage concentration of high level borehole is 19.85% to 23%. The values of gas concentration of upper corner and working face are 0.15% to 0.48% and 0.08% to 0.45%. The (4-5)04 working face is mined safely and effectively.