Abstract: The investigation of the adsorption capacity of RFS09 SOx transfer for simulated FCC regeneration flue gas was conducted in a small-scale fluid bed unit. The experimental results indicate that SO2 removal rate of SOx transfer is step down at some time point with the extension of running time. The accumulated adsorption capacity indicates a gradually increasing trend with running time. It increases quickly at the beginning of reaction and then goes up slowly. The absorption capacity per weight of SOx transfer in unit time decreases gradually and steps down at some time point. The accumulated absorption capacity of the SOx transfer increases with increase of loading, but it is not a simple amount of amplification. The research results indicate that there is an economic usage amount of SOx transfer in commercial unit for the largest SO2 accumulation absorption capacity per weight of SOx transfer.