Abstract: It is necessary to conduct cold simulation of pretreatment of refractory gold concentrate (RGC) in there-phase fluidized bed, providing key parameters of subsequent hot experiments. Air, water and HGC were used as gas phase, liquid phase and solid phase, respectively. Through theoretical analysis and experimental study, hydrodynamics in three-phase circulated fluidized were studied. The effects of operation conditions on the flow Characteristics were conducted. (1) average gas holdup increased with gas velocity exponentially; liquid circulation velocity increased with gas velocity, and gas-liquid mass transfer mainly occurred in the upper tube; average gas holdup increased with amount of solid particles. (2) At the initial stage, with the increase in gas flow rate, pressure drop between two points dropped. The pressure drop of upper part is the largest, the lower part is the second, the central is minimum. With a further increase in gas flow rate, pressure drop slightly decrease. (3) Under the experimental condition, the correlation of average gas holdup in circulating fluidized bed is ε_g= 0.12U_g^0.99.