A newly developed filtered density function (FDF) transport equation was used to describe the fluid velocity seen by the particles in two-phase flows and the interaction between the two phases was considered. Numerical simulation of a gas-particle two-phase backward-facing flow was carried out with the LES/FDF model, in which the large eddy simulation (LES) was used for the gas-phase. The numerical results were compared with the experimental data. The comparison shows that the LES/FDF model can distinctly improve the precision of the simulation. Further investigation has been carried out on the turbulence modification by particles with different particle parameters. (C) 2011 Elsevier Ltd. All rights reserved.