Abstract: Aiming at the problem of low drilling depth and low porosity in borehole construction of soft outburst coal seam, this paper analyzed and summarized some technical methods and problemsdifficulties existing in drilling construction of soft outburst coal seam, and put forward a high rotation speed wind pressure spiral composite slag discharging technology，the technological principle was expounded and the technological parameters of high speed compound slag drilling were analyzed and determined. The practice shows that the high speed drilling BHA and supporting with 95/60.3 plug-in sealing type spiral drill pipe and 98 arc-shaped matrix PDC bit, hole rate increased to 70.6%, the drilling depth is also significantly improved, also it provided referencepractical experience for drilling in soft outburst coal seam.