Yuxi Mine belongs to coal and gas outburst, two quaternity outburst prevention should be conducted before mining, crossing layer pre-drilling coal seam gas was adopted in working face roadway, position of the bottom suction lane and the angle of the perforation hole are the key of solving construction difficulty and reduce invalid drilling. Reasonable level selection of bottom suction roadway and optimized drilling were given based on comparison and calculation, with good economic benefit after construction.