Abstract: Due to the influence of gas pressure, coal thickness change, tectonics and other factors, the phenomenon of gas jet hole often occurs in the cross-seam drilling during the construction of bottom drainage roadway, which is easy to cause accidents such as gas probe alarm and power failure, and there are large potential safety hazards. By analyzing the principle of gas jet hole and anti spray technology, the original device is optimized and improved to achieve effective separation of gas water slag during drilling. A closed sleeve air supply device is used to reduce the concentration of gas escape in the return air flow of the tunnel. In a closed operating space, the entire drilling process relies on the negative pressure of the extraction pipeline and air supply pressure to suppress gas jet into the tunnel, and the rig efficiency is improved to 2 100 m per month. The gas flow and concentration in the extraction pipeline have been significantly increased, and the gas concentration in the return air flow of the tunnel during operation has decreased to 0.34%-0.37%, reducing the impact of drilling time caused by gas power outage.