The Fischer-Tropsch synthesis (FTS) performances of iron-based catalysts promoted with/without potassium compounds containing different acidic structural promoters (Al 2 O 3 , SiO 2 , and ZSM-5) were studied in this research. Characterization technologies of temperature-programmed reduction with CO (CO-TPR), powder X-ray diffraction (XRD) and M össbauer effect spectroscopy (MES) were used to study the effect of K-structural promoter interactions on the carburization behaviors of catalysts. It showed that the addition states of potassium (K-Al 2 O 3 , K-SiO 2 , K-ZSM-5 and K-free) have a significant influence on the formation of iron carbides, which shows a following sequence in promotion of carburization: K-Al 2 O 3 > K-SiO 2 > K-ZSM-5 > K-free. The FTS reaction test was performed in a fixed bed reactor. It is found that Fe/K-Al 2 O 3 catalyst leads to the highest CO conversion, Fe/K-ZSM-5 catalyst shows the highest H 2 conversion, and Fe/K-free catalyst shows the lowest CO and H 2 conversion. As for the hydrocarbon selectivity, Fe/K-SiO 2 catalyst yields the lowest methane and the highest C 5 + products, Fe/K-ZSM-5 catalyst yields higher methane and the highest liquid hydrocarbon product, whereas Fe/K-free catalyst yields the highest methane and the lowest C 5 + products. These results can be explained from the interaction between potassium and structure promoters, and the spillover of reactants or intermediates from Fe sites to the surfaces of structural promoters.