Abstract: Objective In the process of filling mining in coal mine, it is found that due to the physicochemical interaction between filling slurry and the influence of goaf environment, interference gas will be generated, causing the false alarm of KGA5 mine CO sensor used in underground. Method Based on the above problems, by using the normal temperature oxidation test device and the normal temperature oxidation gas test system of slurry, the gas production characteristics of filling slurry based on the normal temperature oxidation of coal gangue, cementation powder, fly ash and mine water were studied. Result Results show that the filling slurry based on cementing powder will consume O₂ and CO₂ in the physicochemical reaction process, and will generate CO, H₂ and NH₃.Conclusion The maximum yield of CO, H₂ and NH₃ in the physicochemical reaction of the whole-component filling slurry based on cementing powder-based is about 8.789×10^-4 ppm/(kg·m³), 1.39×10^-3 ppm/(kg·m³) and 1.707×10^-3 ppm/(kg·m³), respectively. In addition, it is concluded that H₂ is the main cause of false alarm of KGA5 mine CO sensor after cross interference experiment, whose range is 0.4～0.5.