Based on the statistical analysis of 76 drilling tool breaking accidents in Chuanqing gas drilling from 2005 to 2021, this paper concludes that the main causes of drilling tool failure in gas drilling are drilling tool fatigue, vibration, chemical corrosion and high speed erosion damage. When drilling with air hammer, the instantaneous neutralization point of the drilling string moves up under the impact force, and the fatigue point is not necessarily concentrated in the 228.6 mm drill collar near the bit. The vibration of drill string in high frequency band has little influence on the damage of drill string, while the vibration of drill string in low frequency band causes low order resonance of drill string, and then results in the vibration failure of drill string. When gas drilling is carried out under the condition with formation water production, dissolved oxygen corrosion and weak acid corrosion of carbon dioxide are easy to occur in drilling tools, resulting in the pitting damage of drilling tools. Bottom hole cuttings with high velocity gas flow impact the drill string intermittently. Erosion is the main cause of drilling tool wear failure. Based on the analysis of the above reasons, this paper puts forward specific countermeasures from such aspects as drilling assembly optimization, improving the corrosion inhibition technology of atomized base fluid and gas injection parameters, so as to provide reference for reducing the failure probability of drilling tools in the later gas drilling operations.