Abstract: Taking the explosion of a 10 kg TNT explosive device in an open, breezeless zone as the background, the states of the detonation products at 1 ms after the explosion were calculated using Autodyn, which provided reliable source term geometric models and physical parameters for the numerical simulation of the particle motion in the explosion plume. Then a double-layer source term model was established using GAMBIT. Finally, by importing the model into Fluent software, a discrete particle model (DPM) was developed. And by using the developed DPM, the particle trajectories of the particles of the sizes of 1, 10, 50 and 100 m, were calculated systematically, the distribution and movement trends of the different size particles in the smoke rising process were analyzed, and the particle concentrations at different heights were given.