Including the effects of particle-particle collision and particle rotation as well as the volume of particle occupied in the fluid, the Computational Fluid Dynamics (CFD)-Discrete Element Method (DEM) approach could properly predict the behavior of gas-solid flow with strong coupling and the motion of non-spherical particle, thus show good potential in simulations of alveolar region and fibrous particle transport and deposition. CFD-DEM has been developed to investigate the particle transport and deposition characteristics in human airway. An idealized pulmonary airway model of generations 3 to 5 has been established using the same geometric parameters as previous experiment conducted by Kim and Fisher (C. S. Kim and D. M. Fisher. 1999). The predicted deposition efficiencies are in good agreement with experimental data. Thus. CFD-DEM could properly simulate the particle behaviors in pulmonary airway. Based on the simulations, particle motions are studied by analyzing the particle positions at different time intervals. The results show that the initial position of particle would notably affect its trajectory. The near wall particles distribute evenly in the daughter tubes when they cross the airway. The most centered particles at inlet travel through the model via the inner side tubes of generation 5. The trajectories of other particles would shift from the inside tubes to the lateral ones of last generation as the distance between particle initial position and tube center increases. (C) 2012 Published by Elsevier B.V.