Abstract: Smoke flow is affected by various factors during the roadway fire. To study the law of smoke diffusion and disasters during fire period, the numerical simulation for L-type roadway based on FDS is carried out. Refer to the wind speed specified in the Safety Regulations for Coal Mines, flue gas spread, temperature and CO concentration changes in mine fires at wind speed range of 0.25 m/s to 2.1 m/s under 1.92 MW and 2.7 MW fire source power are simulated. The results show that the fire source power and the wind speed have great influence on the smoke diffusion, and the leeward side exhaust velocity is positively correlated with the fire source heat release rate and wind speed. Due to the existence of critical wind speed, the heat release rate has a different relationship with the backflow of smoke in the windward side. When the wind speed is too low, the flue gas diffusion velocity on the windward side depends on the power of the large fire source; when the wind speed increases to the critical wind speed, the influence of the fire source power on the flue gas reverse flow velocity and distance decreases or even disappears. The temperature of the roadway is consistent with the influence of the fire source power and the wind speed. The temperature decreases from the fire zone of the roadway to both sides, but the temperature of the large fire source power tunnel is higher than that of the low fire source power.