The gas-solid flow in a 3-D bubbling fluidized bed is numerically simulated with the coupling of computational fluid dynamics (CFD) and discrete element method (DEM). The gas phase is described by the Navier-Stokes equations while the solid phase is tracked individually. The distribution properties of the local and global dispersion coefficients of solid phase are initially investigated. The granular temperature of solid phase is studied to capture its turbulent behavior. Then, solid circulating pattern is explored. Besides, the influences of superficial velocity, the particle diameter and the scale-up of the bed width on these aspects are discussed. The results show that the vigorous lateral dispersion of solid phase appears in the central region near the inlet, while intensively vertical ones exists in the region of bubble eruption. Furthermore, the vertical dispersion intensity of solid phase is larger than the lateral ones in nearly an order of magnitude. Vigorously turbulent behavior of the solid phase is observed to be in the upper central region of the bed. The larger the superficial velocity or the smaller the particle diameter, the enhanced dispersion and more chaotic motion of solid phase appear. The scale-up of the bed width not only enlarges the lateral dispersion intensity but also leads to more chaotic and turbulent motion of solid phase. Besides, three patterns of solid circulation can be observed, namely the gross circulation, the local circulation and the local exchange. The numbers and intensities of both gross and local circulations increase with enlarging the superficial velocity. (C) 2014 Elsevier B.V. All rights reserved.