In order to determine the reasonable spacing of boreholes for gas extraction in coal seam of high gas mine, the effective extraction radius of boreholes was studied by field test of borehole gas flow method. According to the relationship between the pure amount of gas extraction and extraction time, combined with the occurrence of coal seam gas and the effective length of boreholes, the effective extraction radius of different extraction days under different extraction rates was analyzed, and the reasonable spacing of boreholes for gas extraction in bedding boreholes was determined, which effectively improved the efficiency of gas extraction. The results show that : ①The extraction radius of the measured boreholes gradually increases with the increase of extraction time, but the increasing trend gradually decreases and eventually tends to the limit value ; ②The extraction rate increases from 30% to 60% according to the equivalent 10 %. Under the same extraction time, the effective extraction radius first decreases greatly and then decreases slightly with the increase of extraction rate.