Abstract: The characteristics of space objects are very important for the space-borne optical sensor. This paper analyzes the characteristics of distribution and geometry of the space objects, and summarizes the reflectivity of major materials used by satellite. Visible light scattering characteristic of the space objects are discussed specially. Firstly, solar radiation is calculated. Secondly, radiation luminescence calculation models of the two basic diffuse reflection surfaces of satellites are established. The simulation program of optical characteristic of space object is proposed. The simulation system of visible light scattering characteristic of space objects is set up. The simulation system can change the observation distance, photometric magnitude and the sun light phase at real time. Then two validate methods are derived for it is difficult to get real observation data. These validate methods are preferable methods for analyzing space-borne optical sensors. At last, the characteristics of space objects observed by space-borne optical sensor is depicted. This paper provides an effective reference to space-based observation system design.