Abstract: In order to study migration and distribution law of a mine fire disaster smoke in the mine roadway, a PDF non pre-mixed combustion model with a single mixture fraction was applied to the 3D transient numerical simulation. The variation law of the temperature field and the smoke countercurrent layer during a fire disaste r occurred in a drift of a coal mine were analyzed and studied. The results showed that when the fire source intensity was certain, with the solution of the model with 0. 5, 1.0, 1.5, 1.8, 2.0 and 2.5 m/s and other different air intake velocity in the mine fire disaster process, the results showed that there was a limit air velocity existed to pr event the spread and migration of the high temperature smoke to the top air side of the fire source and the limit air velocity Vminin the model was 2.0 ~ 2.5 m/s. Alsoa f unction expression of the air flow velocity for the countercurrent layer was provided. When the air flow velocity was certain, with the solution on the model with 5.24, 10. 48, 15.72 and 20.96 MW and other different fire source intensity in the fire disaster process, the results showed that under the different fire source intensity, the transie nt variation law of the temperature field within the mine roadway was obtained and a function expression of the fire source intensity for the countercurrent layer was pro vided.