This paper describes spinwaves localized states and the coherent magnon transport via magnetic interface between two different Heisenberg ultrathin ferromagnets films A/B and the inverse B/A. The model system consists of two semi-infinite ferromagnetically ordered slabs A and B, with different structures and the same thickness, joined together. The crystalline thin films A and B have, respectively, simple cubic and hexagonal meshes. The transmission of magnons, scattering coherently at the interface boundary and localized spin states are calculated and analyzed for the both films A/B and B/A. The theoretical calculations are carried out using the matching method. Transmission and reflection scattering cross sections are determined from elements of a Landauer type scattering matrix. The results highlight the localized spin states on the interface domain and their interactions with incident magnons. The results demonstrate also the magnetic properties of thin films at a microscopic scale. The calculated properties are presented for all accessible frequencies in the propagating bands, and for the interatomic magnetic exchange of the A and B films, and their spin intensity, with no externally applied magnetic field. The magnons modes associated with interface domain, in layered structures, interact with propagating modes of the perfect films, located on both sides, leading to interesting magnetic behaviors. Published by Elsevier B.V.