Bubble dynamics are very important in the design of fluidized beds because they govern hydrodynamics and efficiency of the operation for which the bed is used. A numerical simulation work of two-dimensional gas-solid fluidized bed based on discrete element method (DEM) was carried out in this paper. In order to study bubble statistical properties of a large number of bubbles, the flood fill concept was introduced in this paper to search the bubbles, which used the simulated voidage data directly. Various bubble properties i.e. bubble size and velocity distributions, bubble shape factor and aspect ratio, can be obtained simultaneously using this analysis method. The calculated results of bubble properties are in sound agreement with previous empirical correlations and experimental data in literature. (C) 2015 Elsevier B.V. All rights reserved.