The invention provides a benzocyclobutene monomer containing adamantane and hexafluorocyclobutane structures, and a preparation method thereof. The benzocyclobutene monomer is shown in a formula (IV) which is described in the specification. According to the invention, adamantane with a great rigid structure and hexafluorocyclobutane with a great number of C-F bond structures are introduced into a benzocyclobutene structure, so preparation of a polymer with a low dielectric constant and good thermal stability is made possible. The invention further provides application of the monomer in preparation a polymeric material. A polymer prepared by subjecting the monomer to heating and polymerization has good thermal stability, a low dielectric constant and good film forming performance; a polymer film thereof has excellent surface smoothness and excellent hydrophobicity and is expected to be applied to the field of products of high-performance dielectric layer materials and substrate materials.