Abstract: The precise detection of the relative position and attitude between spacecrafts is very important, which is the base of autonomous control for spacecraft formation-flight. In order to solve the problem of the relative position and attitude measurements between spacecrafts with high precision at long distance, a method based on superresolution image reconstruction is presented. Firstly, the principle based on single image is introduced. Secondly, the degraded imaging model of camera and the algorithm of image registration are studied. Thirdly, the algorithm of image reconstruction and the algorithm flow chart based on superresolution are proposed. Finally, the validity of the algorithm is tested by the real data from the ground prototype system . The results indicate that the effective distance and precision are greatly improved, which effectively solved the problem of spacecraft relative state measurement precision and stability.