Abstract: SAR images have strict requirements on the accuracy of radiometric calibration in the measurement of geophysical parameters and the realization of quantitative remote sensing applications.Therefore，the radiometric calibration verification of the SAR satellites is carried out.The relationship between the backscattering coefficient，the calibration constant and the image DN value is calculated with the radar equation，and the calibration verification experiment is carried out by using the active calibrator of Ningxia Zhongwei Calibration Field and its SAR image.The experimental results show that the absolute radiometric calibration accuracy of GF-3 02 satellite data is very high，in which the integration radiometric calibration accuracy is 0.65dB，while the peak calibration accuracy is 0.57dB；the radiometric calibration accuracy of the HISEA-1 satellite data is about 1.2dB.Maintaining the same wave position when calculating the calibration constant can effectively improve the stability of the calibration constant.

Key words: absolute radiometric calibration, absolute calibration constant, integration method, peak value method, wave position