Abstract: To study the influence of common combustible gas produced in spontaneous combustion of underground coal on methane explosion, the effects of the mixture of C₂H₄, C₂H₆, H₂ and CO on the maximum explosion pressure and temperature of methane were simulated by FLACS software at 5 initial temperatures (25, 60, 100, 140 and 180 ℃). The results show that, with the increase of initial temperature, the maximum explosion temperature of methane and the maximum explosion pressure show an upward trend, while the maximum explosion pressure shows a downward trend. With the increase of the volume fraction of the four combustible gases from 0.4% to 2.0%, the maximum explosion temperature and the maximum explosion pressure of methane increased even more when the initial temperature was lower.