Abstract: For gas drainage holes in soft and outburst coal seams, there are three technical bottlenecks, firstly it is difficult to form a hole, secondly the probability of hole formation is low, thirdly there are many downhole accidents such as tools truck and gas gushing from the hole. Aiming at these three actual issues, through analyzing the powder discharge mechanism and the drilling technology of spiral drill pipes, as well as the field application of different types of non-standard large-bore spiral pipes with wide wing blade, it is summarized that the drilling technology and auxiliary equipment of non-standard spiral pipes are suitable for different soft coal seams so as to popularize and apply them.