The analytic expressions for the scattered distributions at the focal plane of the Ritchey-Chretien reflective system (R-C system) from the primary mirror and the second mirror were derived. Aiming at the scattered distribution in a typical R-C system, the excellent agreement of the computing results according to the formula introduced in this study with the simulating results provided by the commercial optical analysis software shows that the formula derived is believable and reasonable. Compared with the diffracted distribution at the focal plane, it is more convenient to analyze the saturated effects at the focal plane of the system irradiated by intense light. The results indicate that in the typical R-C system, diffraction is the dominant factor of the saturating effect inside 2.5mm, while surface scattering saturates the detector outside this range. This result provides a theoretical basis for the further study of intense light induced saturating effects in optical system. 