In a fluidized bed boiler, the existence of the large particles will make the fluidization phenomena deteriorate. In order to discharge the large particles more effectively, it is crucial to understand well the dynamic characteristics of the large particles in the fluidized bed. A cold experiment was carried out on a fluidized bed with the Lambda - shaped air distribution plate, and the Euler dual-fluid mode was employed in the computer simulation, respectively. It is found that the shape and density of the large particles have the most significant influence on average residence time, while the influence of the fluidized air velocity and the particle size is relatively small. Moreover, the mechanisms controlling the residence time and movement behavior of the large particles with the different shapes were gained by analyzing the flow-field distribution of the gas-solid two phases and the evolution of force acting on the large particles. (C) 2020 Elsevier B.V. All rights reserved.