Abstract: Composite sandwich structures are widely applied in curved structural components, such as aircraft radomes. However, the influence of structural curvature on the mechanical behavior and deformation modes of fiber-tape reinforced sandwich curved beams remains unclear. Therefore, the mechanical properties and deformation mechanisms of fiber-tape reinforced carbon fiber/aluminum honeycomb sandwich curved beams were investigated based on a three-dimensional finite element model. The accuracy of the numerical model was validated through three-point bending tests on sandwich straight beams. On this basis, the effects of curvature, fiber-tape reinforcement efficiency, core wall thickness, and face sheet thickness on the mechanical performance of the curved beams were studied. As the curvature increased, the load plateau in the initial failure stage of the sandwich curved beams was significantly extended. The reinforcement efficiency of the fiber tapes followed a non-monotonic trend; the most pronounced effect was observed in straight beams, where the peak load increased by approximately 18.9%. Increased core wall thickness effectively delayed buckling instability and shear band expansion, but it intensified face sheet stress concentration and induced plastic hinge failure. Although increasing face sheet thickness enhanced the ultimate load by over 80%, the combination of high curvature and large face sheet thickness caused the fiber tapes to fracture due to overloading, resulting in severe load fluctuations. The results indicate that the coupling between core shear band expansion and fiber-tape synergetic deformation is the primary factor influencing the deformation behavior of fiber-tape reinforced sandwich curved beams across various curvatures.