Abstract: Air drilling technology may raise drilling velocity in hard formation,but is easy to cause underground explosion leading to drill tool damage.After analyzing the reason of underground explosion,it is put forward that using nitrogen drilling technology is the most simple and universal method for solving that problem.The equipments needed in nitrogen drilling construction such as compressor,nitrogen machine,booster compressor,rotary blowout prevention machine,and so on and their functions are introduced.Meanwhile,construction technology,flow and process of Puguang202-1 are analyzed by nitrogen drilling test in the said well.The successful application of nitrogen drilling technology shows that nitrogen drilling,which has good application prospect,not only solves underground explosion prevention problem efficiently,but also improves drilling aging by increasing mechanical drilling speed by 5 times above and reducing quantities of drilling bit.