Basing on the theory of gas-solid two-phase flow and the characteristics of flat-type chamber stope,the model of dust migration was established.k-ε two-equation model and DPM(Discrete Phase Model) of fluent software was used to perform the numerical simulation no the dust concentration transformation in ventilation of 20 minutes after blasting and the movement locus of dust under different inlet wind speeds.The results showed that the flow field of airflow has a significant effect to the distribution of dust concentration.The dust gathers on the left corner of chamber and in the vicinity of chamber’s side wall in 0-50 s after blasting,then,is carried away from the chamber by the main stream 50 s after blasting,and comes to the stage of the circular net emission after 60 s.The concentration of dust falls most quickly in 0-70 s,after 70 s it is mainly respirable dust,needing a long time to settle.The numerical simulation of dust migration showed that the different inlet velocities have a significant effect to the dust migration.