Abstract: In order to reduce the gas concentration in the upper corner of U-shaped ventilation working face in close distance multi seam with high gas and hard roof and improve the gas drainage efficiency, the high-level boreholes in 143 fully mechanized mining face of low permeability and high gas coal seam in Donggou coal mine of Xinjiang are taken as the research object.Based on the theoretical analysis of the influence of hydraulic presplitting on gas drainage effect, the hydraulic presplitting test of upper corner suspended roof is carried out, and the work is summarized.According to the theoretical calculation results of effective length and utilization rate of boreholes, reasonable spacing of drilling field, number of boreholes, arrangement horizon, spacing and inclination of stubble, control range and other parameters, combined with the development law of overburden fractures, optimization design of high-level borehole layout, final hole position, final hole spacing and number of boreholes and other extraction process parameters.The field practice shows that the position of the drilling site is increased by about 1 m on the basis of the floor height of the return air roadway after the optimization of the extraction process parameters, the final hole height is controlled at 15-25 m, the distance between the final hole and the return air duct is 1-41 m, the final hole spacing is 8 m and the number of boreholes is 6, the drainage efficiency and capacity of high-level boreholes are significantly improved, and the gas concentration in the upper corner is reduced to 0.1%-0.3%.