Abstract: To study the propagation of gas explosion shock wave and flame in coal mine heading face at real scale, the numerical simulation software of gas explosion was used to establish roadway models of different scales, and the influence of premixed gas concentration, premixed gas length and roadway spatial characteristics on the overpressure and flame propagation was studied. It is found that the maximum overpressure of gas explosion in heading face can reach 180-630 kPa under the original scale. The constraint degree of roadway section and premixed gas amount are important control factors of gas explosion pressure and flame range. The resistance of high-speed flame propagation will lead to slow flame diffusion and eventually make the flame expansion ratio tend to a certain value.