Lattice-Boltzmann simulations on fluidization of two-dimensional rectangular multi-particles falling against gravity are performed. The particle behavior is dominated by inertia effects associated with wakes. The long bodies of the rectangular particles turn horizontal dominantly. Relative stable particle clusters and inverted T clusters are found. Drafting, kissing and melting can be used to characterize the behavior of multi-rectangular particles. Simulation results are well consistent with the experimental results of three-dimensional cylindric and disk particles. (C) 2000 Elsevier Science Ltd. All rights reserved.