Abstract: A series of FeMn/MgO catalysts were prepared by wetness impregnation method and different MgO which came from commercial MgO, thermal decomposed MgO and that prepared by co-precipitation method were used as supports. The catalytic performances of these samples for light alkenes synthesis through CO hydrogenation were investigated, and their properties were characterized by XPS, BET, XRD and H₂-TPR techniques. These results showed that the sample supported on the co-precipitated MgO had the highest surface area (203.5m²/g), and had the highest activity for light alkenes synthesis through CO hydrogenation. Under the conditions of 340℃, 2.0MPa and 1600h^-1, the CO conversion and the selectivity of C₂⁼～C₄⁼ reached 91.36% and 58.48%, respectively. High surface area, high content active components well dispersed on the  catalyst surface and the enhanced reduction property were important reasons for the perfect catalytic activities of these catalysts.