Abstract: Due to the comprehensive influence of gravity, stress release, heat and component aging, it is necessary to calibrate the space remote sensor periodically on-orbit. In order to improve the accuracy of spaceborne radiation calibration, an on-orbit calibration method was proposed, combining lunar calibration and solar calibration. Firstly, using lunar imaging, the on-orbit absolute radiation calibration of the central field was carried out, and the satellite ground difference and on-orbit change of radiation characteristics of the instrument were calibrated. Then, using solar calibration, the non-uniformity of the detector was obtained. Finally, the calibration uncertainty of the polarization spectrum imager was analyzed. The results show that the total uncertainty of absolute radiation calibration is 3.77%, meeting the requirement of 5% radiation calibration accuracy. The method proposed in this paper provides an important technical support for improving the calibration accuracy of remote sensors and the detection ability of aerospace load.