Abstract: In order to effectively control underground thermal damage, considering the influence of water evaporation and heat absorption on air flow temperature distribution in roadway, studying the dehumidification and cooling effect of air flow, the function of moisture evaporation changing with rock wall temperature was fitted by the least square method as the basic equation to solve the moisture content in air flow, the finite difference method numerical simulation model for the dehumidification and cooling of roadway was established. Matlab software was used to write a simulation program for calculation, and the stability and convergence conditions were given. The calculation results show that moisture evaporation is an important factor affecting air flow temperature distribution,under the influence of water evaporation, the heat transferred from the surrounding rock to the air does not necessarily increase the air temperature; when the combined cooling method of dehumidification and cooling is adopted, the airflow cools rapidly and the effect of continuous cooling is maintained for a long period in roadway.