As part of the spacecraft optical loads, space camera will be subject to all working components in aircraft and space environment disturbance on-orbit, which have great influence on image resolution and image contrast, especially for large-aperture Ritchey-Chretien (R-C) optical system. This article puts forward a new method about estimating image quality degradation induced by micro-vibration. With the space coordinate transformation, the amount of optical elements jitter expressed by six variables are acquired, then the data can be imported to optical design software Code V, image motion and the root mean square(RMS) diameter will be quickly attained, then the image quality could be judged. The simulation and analysis are of significance for studying the influence of satellite micro-vibration on imaging system. For high resolution large-aperture R-C imaging system, this study provides important reference for system control and isolation.