Hydrodynamics of gas-particle two-phase turbulent flow in a circulating fluidized bed riser is studied experimentally by particle image velocimetry (PIV) and numerically with the use of a 3D discrete hard sphere particle model (DPM). The influence of the superficial gas velocity and the solids flux on the flow patterns at different vertical positions has been investigated. Mean particle velocities and rms velocities are obtained, and the influence of turbulence oil the flow is investigated. It was found that the superficial gas velocity has a strong influence on the vertical solids velocity but only a minor influence oil the extent of solids downflow. The solids flux has a large effect on the extent of solids downflow but only little influence oil the lateral profile of the rms vertical solids velocity. The experimental data are analyzed and compared with the numerical results showing a reasonable agreement.