The application of remote sensing technology to the mapping is the development trend of modern geological mapping technology. With the increasing resolution of optical load,mapping remote sensor has become an important guarantee for social development and the development of the national economy. Optical load which is the core component of remote sensor determines the resolution of mapping space remote sensor,the precision of mapping,and the volume and weight of the satellite platform. Structure and optical properties of the mapping space remote sensor optical system are introduced,such as high image quality refractive system,co-axial three mirrors system and off-axial three mirrors system. Then,structure and optical properties of new space reflective optical system in development are prospected. Analysis result indicates that according to different application environment and technical index,different types of optical system should be selected reasonably,so the platform resources can be used fully to meet the demand of mapping remote sensor.