Abstract: Bending deformation constitutes one of the most prevalent forms of mechanical behavior in engineering structural components and serves as a foundational topic in mechanics of materials. The characterization of bending internal forces underpins the comprehension of bending-related principles. This study systematically investigates the representation of bending internal forces from both graphical analysis and experimental testing perspectives. First, employing straight beams and rigid frames as analytical models, a unified graphical methodology for constructing bending internal force diagrams is proposed to address pedagogical bottlenecks caused by ambiguities in existing approaches. Second, by integrating approximate differential equations of the elastic curve with Digital Image Correlation (DIC) technology, a novel full-field deformation-based characterization method is developed. This approach establishes an integrated framework combining experimental techniques, deformation theory, and internal force computation, thereby enhancing students' conceptual understanding of bending deformation mechanisms. The proposed methodology fosters innovative thinking and interdisciplinary synthesis capabilities, offering a robust pedagogical strategy for advancing structural mechanics education.