Abstract: The spontaneous combustion of residual coal in goafs can lead to the waste of coal resources and cause serious safety accidents. Nitrogen injection technology for fire prevention and extinguishing is an effective solution to address the issue of spontaneous combustion of residual coal in fully mechanized working face goafs. This paper systematically elaborates the principles and processes of nitrogen injection for fire prevention and extinguishing in goafs. It analyzes the relevant technical parameters of nitrogen injection technology from three aspects: nitrogen injection location, nitrogen injection pipeline, and nitrogen injection flow rate. Additionally, an engineering effectiveness verification is conducted. The engineering test results of the 8112 working face in Anping Coal Mine show that after nitrogen injection into the goaf, the CO concentration in the goaf decreased to below 0.0013%, and the CO concentration in the upper corner dropped to 0.0008%. During the mining period, no spontaneous combustion of residual coal occurred in the goaf, verifying the effectiveness of nitrogen injection technology for fire prevention and extinguishing in goafs.