Abstract: To determine the important nitrogen injection process parameters, such as the reasonable nitrogen injection flow rate, the nitrogen injection pipeline spacing and the initial nitrogen injection depth in the goaf, the beam monitoring system is continuously monitored on the return air side of the working face to monitor the variation laws of O₂ concentration in the goaf of the return air side, and study the distribution law of spontaneous combustion “three belts” in the goaf under different conditions of nitrogen injection flow and nitrogen injection pipeline spacing. The results show that the reasonable nitrogen injection flow rate of the short-arm high-level fully mechanized caving face in Wudong Coal Mine is 259 m³/h to 622 m³/h, and the distance between the full-section nitrogen injection pipelines in the goaf is 20 m to 40 m, and the initial nitrogen injection position is 15 m behind the shelf.