<p>The dynamic modeling of continuous fiber-reinforced composite structures is investigated in this paper. It comprehensively considers multiple mesoscopic factors, with particular emphasis on the fiber cross-sectional shape during the modeling process. Therefore, the traditional Eshelby tensor is enhanced to accommodate not only elliptical fiber inclusions but also arbitrary polygonal fiber cross sections. This improved representation of the Eshelby tensor is relatively simple and effectively reduces computational complexity. By incorporating the interactions between fibers in the material to a certain extent, the enhanced Eshelby tensor is applied to the Mori–Tanaka average stress method. This approach allows us to solve the stress–strain relationship between fibers and the matrix, thereby establishing a mesoscopic mechanical model that features arbitrary polygonal fiber cross sections. Building on this mechanical model, dynamic modeling of a fiber monolayer structure is conducted. Furthermore, based on this monolayer model, a vibration characteristic equation that accounts for the presence of multiple fiber components within the same matrix is proposed, thereby enhancing the mesoscopic structure. Finally, using a TC300 carbon fiber/resin-based composite thin plate as the research object, the accuracy and reliability of the proposed mesoscopic theoretical model are verified through numerical simulations and experimental validation. Additionally, the effects of fiber angle, thickness, fiber content, and fiber cross-sectional shape on the natural characteristics (natural frequencies and modal shapes) of composite materials are studied.</p>