To study the temperature changing process inside roadway after coalmine explosion, this paper built a simplified mathematical physical model of roadway after coalmine explosion, analyzed the effect of convection coefficient and density on the basis of thermodynamic equation, and got the curve of air temperature changing. To avoid generating excessive error because of simplifying the convection heat transfer model, the unsteady gas-solid coupling heat transfer was analyzed with Fluent to obtain the process information of temperature changing in roadway. The two curves match each other highly. The results show that the period of high temperature inside roadway after explosion won’t last long, which provides reference for the parameter design of mine refuge chamber and rescue capsule.