K_2O and MnO are two kinds of necessary promoters to theselective production of light alkenes from CO hydrogenation over silicalite-2(Si-2) zeolite supported Fe catalyst. The addition of both K_2O and MnOpromoters into Fe/Si-2 catalyst leads to a remarkable increase in the COconversion and the selectivity to light oletins. Silicalite-2 zeolite as Fe-MnOcatalyst support can suppress the formation of α-Fe_2MnO_3 or/andα-Fe_(2-y)Mn_yO_3 as Well as α-Fe_2O_3 and/or α-Mn_2O_3, being favorable for(?)ncreasing the dispersion of active metal component. So MnO can promotethe reduction of Fe~(3-) and enhance the capacity of CO adsorption, which canimprove the activity of the activity of the catalyst for CO hydrogenation. While K_2Opromoter is unfavorable for reduction of Fe~(3-) to some degree with formation of Fe~(2-) as a new species after reduction. However, K_2O promoter can enhance the capacity and strength of CO adsorption greatly.So K_2O can alsoimprove the activity of catalyst for CO hydrogenation. K_2O and MnO are two kinds of necessary promoters to theselective production of light alkenes from CO hydrogenation over silicalite-2 (Si-2) zeolite supported Fe catalyst. The addition of both K_2O and MnOpromoters into Fe / Si-2 catalyst leads to a remarkable increase in the COconversion and the selectivity to light oletins. Silicalite-2 zeolite as Fe-MnOcatalyst support can suppress the formation of α-Fe_2MnO_3 or / andα-Fe_ (2-y) Mn_yO_3 as Well as α-Fe_2O_3 and / or α- Mn_2O_3, as favorable for (?) Ncreasing the dispersion of active metal component. So MnO can promotethe reduction of Fe ~ (3-) and enhance the capacity of CO adsorption, which can improve the activity of the activity of the catalyst for CO hydrogenation. While, K_2Opromoter is unfavorable for reduction of Fe ~ (3-) to some degree with formation of Fe ~ (2-) as a new species after reduction. However, K_2O promoter can enhance the capacity and strength of CO adsorption greatly.So K_2O can alsoimprove the activity of catalyst for CO hydrogenation.