Failure of drill pipe is very severe in gas drilling. Based on the erosion theory and field condition, the erosion of drill pipe is investigated by using numerical simulation. The agreement between the simulation result and experimental data is very good, this agreement indicates that the numerical model is realistic in this paper. The erosion wear of drill pipe is investigated in gas drilling and mud drilling by using this model. According to study result of drill pipe erosion between gas drilling and mud drilling, the erosion rate of drill pipe in gas drilling is greater than that of in mud drilling. The result shows that the local erosion rate of joint is more severe than that of the drill pipe body in gas drilling, and also the local erosion of drill pipe body is severe. There are many eroded pits on drill pipe body in gas drilling. This study will reveal the failure mechanism of drill pipe in gas drilling, and also have some guiding significance to reduce the failure of drill pipe.