The CFB-FGD process is a semi-dry flue gas desulfurization technology used at the end of the boiler. Considering multiple complex chemical reactions in the desulfurization tower,the mixing level of the gas-liquid-solid in the desulfurization tower would be one of the dominant factors of the reactions. Considering the high cost to build the desulfurization test bench,this paper presented a numerical simulation for flow field of desulfurization reactor using a pseudo-homogeneous fluid model in order to improve the flow field in the circulating fluidized bed desulfurization reactor with nonuniformity generated by its nozzle angle. The influencing mechanism of nozzle angle (-30°,0° and 30°) on the gas-liquid-solid flow field in the desulfurization tower was discussed. The results showed that at nozzle angle of -30°,the nonuniformity of the flow field was reduced in the circulating fluidized bed the volume fraction distribution of the desulfurizer particles had better uniformity and the mixing of the gas-liquid-solid three phase was better,resulting in a better efficiency of desulphurization.