Abstract: Through establishing adiabatic roadway with a length of 4 m and a cross-section area of 80 mm×80 mm, the explosion characteristics of methane/air pre-mixture with fuel concentration of 9.5% are studied by using AutoReaGas software. The results show that the fore shock wave has not yet been formed before the distance of 1.2 m away from the ignition source, and one history overpressure curve has only an extreme value. After the distance of 1.4 m from the ignition source, the fore shock wave and flame front respectively form two extreme values. With the distance increasing from the ignition source, the maximum overpressure gradually decreases and reduces to the minimum of 160.459 kPa, and then it begins to increase and reach the maximum of 204.235 kPa. After that, the maximum overpressure also begins to decrease. The flame propagation speed is 212.5 m/s at the distance of 0.72 m from the ignition source, and it increases to 381.3 m/s at the distance of 3.2 m. The flame speed gradually increases with the propagation distance increasing.