Abstract: In order to find out the main sources of gas emission during drilling and clarify its change law, this paper takes Jiulishan Mine in Jiaozuo Mining Area as an example, and expounds the source, emission and variation law of gas emission during the drilling of floor rock roadway by measuring the amount of gas emission from coal pile and the gas concentration with different distances from the borehole to the windward side of the borehole. The results show that the amount of gas released from the coal stockpile is relatively low, and the gas volume fraction will not exceed the limit through normal ventilation. During normal drilling, the gas emission from the borehole is relatively high, and the gas concentration changes continuously at different distances from the borehole, and the overall trend is gradually decreasing. However, the gas concentration may still exceed the limit at the position 2 m away from the downwind side of the borehole.