R-C optical systems have been widely used in long focal length imaging and long-distance detection fields such as aerospace, remote sensing, exploration, and space optical communication. However, the significant wavefront aberration in the edge fields of R-C optical system always restrict the imaging system in a small field of view. In this paper, the improved R-C optical system is composed of two reflective mirrors as well as three refractive elements, which can correct off-Axis aberrations in large fields of view, enable the large field of view imaging. For the high accuracy assembly, optical centering assembling technology based on optical imaging principle is applied to ensure the coaxiality between the optical axis of optical element and the rotation axis of corresponding machine part. And the reverse optimization method is carried out to compensated the wavefront aberration introduced by misalignment errors. Finally, the testing optimization result of system wavefront aberration with RMS value of center of view is 0.045λ (λ=0.6328nm), and the RMS value of off-Axis field better than 0.08λ can be achieved. © COPYRIGHT SPIE.