In order to achieve high-quality imaging while simplifying the structure and reducing the size of the optical system, a miniature dual-disc folding reflection optical system was designed. A design approach incorporating reflector fitting is employed; the adjacent reflector is fitted to one mirror. The optimized optical system contains two mirrors, and the system length-to-focal-length ratio is 0.325, which significantly reduces the axial distance of the system. Furthermore, the engineering of the optical system was successfully achieved. The experimental results demonstrate that the captured images display consistent clarity, are free from distortion, and meet the specified design requirements.