Flow visualization and analysis was extensively conducted in a bench-scale swirling fluidized bed combustor (SFBC) cold model. An advanced laser-based particle image velocimetry (PIV) system was used to visualize the gas-particle flow in SFBC cold model. The robust experiment design method was applied to study the bed expansion in the SFBC cold model in relationship with secondary airflow ratio. It was found that the secondary airfiow ratio did not affect the bed expansion in the SFBC cold model. Based on the PIV velocity profiles analysis, it was observed that particle velocities increased when secondary airflow ratio is increased. The secondary air was definitely generating the high tangential particle velocity.