Abstract: Radiometric calibration technology is the key link to realize quantitative remote sensing. In recent years, with the maturity of infrared telemetry technology, onboard infrared radiation calibration has become an important development direction of space quantitative remote sensing technology. Based on the background of real-time absolute radiometric calibration of infrared cameras, this paper puts forward the semioptical path on-board absolute radiometric calibration and site absolute radiometric calibration based on multitemperature field. Combined with the experimental data, three schemes of onboard calibration, site calibration and cross calibration are used to verify the on-orbit absolute radiometric calibration experiment. The applicable scenarios of onboard calibration, site calibration and cross calibration are analysed. The results show that by combining the semi and all optical calibration data processing and conversion technology, using the site absolute radiation calibration method of the water surface field and land surface field, a suitable calibration site is selected, and typical ground object scenes are added to the land surface field to realize multitemperature field calibration. The radiometric calibration method proposed in this paper realizes real-time high-precision absolute radiometric calibration, and the calibration accuracy is better than 1.5 K.