针对采空区注氮防火工艺中的采空区瓦斯监测问题 ,提出在同时监测采空区 O2 ,CO,CO2 的条件下 ,使用光学瓦斯检定器测定采空瓦斯浓度 ,给出瓦斯检定器读数的校正原理 ,通过对试验气样的分析结果与校正结果的对比 ,验证了该方法的正确性 ,表明校正结果完全能够满足注氮防火工程对采空区瓦斯监测的需要 Aiming at the problem of gas monitoring in goaf in nitrogen injection fire prevention process of mined-out area, it is proposed to measure the gas concentration of mined-out gas by using gas detector at the same time to monitor gob gas’s O2, CO and CO2, The correctness of the method is verified by comparing the analysis result of the test gas sample with the calibration result, which shows that the calibration result can fully meet the need of the nitrogen injection fire protection project for the gas monitoring of goaf