Abstract: In order to improve the gas drainage effect of high level boreholes,the height of the fractured zone in Zhangcun coal mine is investigated by concentration method,and the layout parameters of high level borehole have been optimized in accordance with the investigation results.The optimized high level borehole extraction technology is used in 2203 working face.The extraction results show that the optimized high level borehole drainage measures can effectively solve the problem of gas overrun at upper corner.