The invention provides a vanadium-based catalyst, including a main catalyst and a co-catalyst, the main catalyst is formed by complexing a vanadium compound and an electron donor, or is formed by complexing a vanadium complex and an electron donor; the vanadium The compound is V(acac)3, VO(OR)3, VO(acac)3, VO(OR)2Cl, VO(OR)Cl2, VCl4 or VOCl3; the ligands of the complexes of vanadium are fatty alcohols, Amines, phosphoric acid esters, β-diketones, octahydroxyquinoline or oximes; the electron donor is a monocyclic aromatic hydrocarbon compound, acrylate compound, methacrylate compound, formula (I) structure The compound of formula (II) structure or the compound of formula (III) structure. The stability of the vanadium-based catalyst to water, air and oxygen is enhanced. When used in the copolymerization of ethylene and propylene, the reaction activity is high, the obtained propylene content is slightly higher, and the structure is controllable.