A two-fluid smoothed particle hydrodynamics (TF-SPH) method was proposed in this work for the simulation of gas solid fluidization, which combines an Eulerian solution of the gas phase and a Lagrangian SPH solution of the solid phase. The basic governing equations of TF-SPH are the same with those of the two-fluid model (TFM). The SPH solution of the solid phase allows significant reduction of the amount of particles that is actually simulated as compared to that encountered in industrial reactors. Thus, it can be expected to speed up the simulation. The sensitivity of SPH parameters to smoothing length and its ratio to particle space was tested. Quantitative comparison was also provided against the experimental data in literature. The TF-SPH method can be expected to be a promising approach for simulation of gas solid fluidization. (C) 2013 Elsevier Ltd. All rights reserved.