The visible and shortwave infrared hyperspectral imager (AHSI) onboard the Gaofen-5 satellite represents a core payload within China′s high-resolution Earth observation program. Unlike conventional off-axis three-mirror cameras primarily used for visible or multispectral imaging, hyperspectral imagers require a specialized architecture comprising a telescope, spectrometer, and detector array. The AHSI features an extended 3-meter optical path integrating three off-axis systems and 22 off-axis optical components, presenting significant challenges in terms of structural complexity, alignment precision, and environmental robustness within constrained space. To address these challenges, this study presents the design and implementation of a novel integrated structural configuration using advanced composite materials. A systematic methodology encompassing material selection, structural design, simulation analysis, and experimental validation is established. The opto-mechanical framework utilizes a high-volume fraction (55% ) SiCp/Al composite as the primary structural material, offering superior stiffness-to-weight performance. The design unifies the off-axis three-mirror telescope, Offner spectrometer, and detector assemblies into a compact and rigid composite structure, optimizing mechanical stability and mass efficiency. The framework is fabricated using an ultrasonic-assisted gradient brazing process to ensure precise bonding and structural integrity. Structural strength and stiffness are confirmed through finite element modeling and mechanical testing. On-orbit imaging results show strong agreement with ground-based calibration data, verifying the design′s environmental adaptability and long-term stability. As the first hyperspectral imaging instrument worldwide to achieve simultaneous wide swath coverage and broad spectral range, AHSI demonstrates the viability of advanced composite-based structural solutions for complex spaceborne optical systems. It delivers critical technical support for strategic national applications, including land resource management and environmental monitoring.