Abstract: The methane oxidation and heat release phenomenon had been found in low concentration methane/air premixed gas (methane concentration is lower than 25% low explosive lever) preheating process in coal mine ventilation air methane regenerative oxidizer. How different concentrations of methane oxidation and heat release effect on premixed gas preheating process were investigated in this paper. The FLUENT software was used for numerical simulation of premixed gas preheating process with unsteady flow field and chemical reaction. The results show that premixed gas preheating temperature is obviously higher than air preheating temperature and surface temperature of regenerative ceramic because of methane oxidation and heat release when methane concentration is higher than 0.2% and preheating temperature is higher than 900℃. When methane concentration of premixed gas increases, the preheating length of premixed gas and quantity of regenerative ceramic decrease at the same time. The numerical simulation results and the experimental results agree well with each other.