Traditional composite laminates with straight reinforcing fibers are prone to buckling failure under in-plane compressive and shear loads, and their limited design space hinders the full exploitation of composite material advantages. This paper focuses on variable-angle-tow composite, employing the Rayleigh–Ritz method for structural dynamics and flutter modeling, while establishing an aerodynamic model for a flat-plate wing and achieving aeroelastic coupling. This method is applicable to rectangular flat-plate wings with low speed and high aspect ratio. A comparison of modal analysis results with MSC.Nastran calculations shows errors of less than 1.46% for the first six natural frequencies. The flutter analysis results exhibit the same trend as those obtained using the software’s classical PK method and meet accuracy requirements. The research conducted in this study is based on analytical/semi-analytical models, providing an in-depth investigation into the mechanical characteristics of variable-angle-tow wing structures while ultimately addressing engineering applications for practical wing design. It demonstrates applicability, high efficiency, and feasibility for manufacturing. The findings offer methodological innovation, engineering significance, and application prospects, serving as a reference for aircraft design departments in the conceptual and preliminary design stages of variable-angle-tow wing structures.