The present invention provides an iron-based catalyst for low-carbon olefin production through CO2 hydrogenation, wherein the main
active component of the catalyst is Fe3O4, the auxiliary agent is added or is not added, and is an
oxide, the content of the auxiliary agent accounts for 0-30% of the total
mass of the catalyst, and the auxiliary agent is one or more than two selected from the
oxide of Si, Al, Mn, K, Cu, Na, Zr, V, Zn and Ce. The present invention further provides a preparation method and applications of the catalyst. According to the present invention, the catalyst has the following beneficial effects that 1) the particles have characteristics of regular spherical shape, uniform
spatial distribution, and narrow size distribution; 2) the raw materials are inexpensive and easy to obtain, and the preparation method has characteristics of simpleness and low cost, and is suitable for industrial production; 3) the catalyst has characteristics of high
mechanical strength, good
wear resistance and compression resistance, and is suitable for the
fixed bed, the
fluidized bed and the
slurry bed; 4) the CO2 hydrogenation activity and the low-carbon olefin selectivity are high, the single-pass conversion rate can achieve more than 40%, the
methane selectivity in the
hydrocarbon product is lower than 15%, the low-carbon olefin selectivity is higher than 40%, the
alkene /
alkane ratio (O / P) is 2-12, and the yield of the low-carbon olefin can achieve 10-60 g / m<3> (CO2+H2).