In order to simplify the support method of the mirror of a ground-based telescope and ensure the imaging quality and accuracy of the telescope, the optimization design of a uniaxial supported SiC mirror with 460 mm aperture was studied. First, a uniaxial support scheme for materials with similar linear expansion coefficients and a fan-shaped mirror back structure were determined. Advanced SiC sintering technology was used to prepare anisotropic structures according to the support structure and the material characteristics. Combined with optimization design theory, the mirror was designed to be lightweight while meeting the required accuracy. The optimized mirror weighs only 4.82 kg, and the RMS of the horizontal simulation analysis of the mirror is λ/51.4. After actual engineering verification, the accuracy detection results of the horizontal state under the mirror support are found to be better than λ/42. The lightweight effect is significant and meets the requirements of practical use. This research provides a theoretical foundation and technical reserve for engineering projects.