The invention relates to a new compound monoimino pyrrole iron and a preparation method and application thereof. A ligand is changed from a parent structure so that the monoimino pyrrole iron has the advantages of novel structure, easy purification, strong water and oxygen resistance and good stability; and the monoimino pyrrole iron is prepared by adopting the steps of: using 2-acetyl pyrrole as a precursor, carrying out condensation reaction with one series of substituted anilines under the condition of microwaves, and complexing with a ferrous compound. The preparation method has the advantages of simpleness in operation, high yield and less byproducts; and by adopting a microwave method, the preparation method is high in reaction speed and simple in operation, can be applied to vinyl polymerization, is capable of effectively limiting the direction and the size of vinyl polymerization to achieve the shearing function on the molecular level of a polymerization product, and has a better industrial application prospect.