A novel flexible composite support structure based on adhesive-metal-adhesive layers is proposed to address the market demands for mass production of remote-sensing cameras. This structure aims to mitigate challenges such as tight assembly tolerances, high manufacturing precision requirements, and the sensitivity of mirror surface quality to assembly stresses and environmental factors (mechanical and thermal). Initially, high-stiffness structural adhesive bonding of metal components post-curing replaces traditional screw connections, with an embedded cylindrical adhesive joint is introduced to enhance assembly tolerances. Subsequently, low-elasticity silicon rubber post-curing is applied to the mirror's lateral surface, accompanied by the introduction of a metal flexible element based on series-parallel plate spring units. Additionally, a metallic flexible element, combining series and parallel plate spring units, is incorporated. The flexibility of the metallic plate springs and silicon rubber reduces assembly-induced stress and environmental disturbances on the mirror surface. Based on compliance analysis theory, the physical compliance model and its relationship with structural parameters are derived and analyzed, with a set of parameters designed for application in a mass-produced camera's mirror support. Comparative studies are conducted using compliance analysis, finite element simulations, and experimental tests on gravity-induced deformation and modal characteristic frequencies. Results indicate that the rigid-body displacement error under gravitational load, calculated using the compliance model, achieves an accuracy better than 6.1%, while the characteristic frequency error calculated using compliance matrix engineering formulas achieves an accuracy better than 10%. Finally, thermal deformation tests show that the mirror surface quality remains within 0.011λ (λ=632.8 nm) after a 4 ℃-temperature variation. The composite flexible support structure demonstrates high adaptability to large assembly tolerances, moderate manufacturing precision, and complex mechanical and thermal environments. It has been successfully applied in the mass production of remote sensing cameras, exhibiting excellent in-orbit performance. This approach provides significant practical engineering value for future applications.