Calibration accuracy can affect the interpretation of microwave radiometer observations and it is the premise of quantitative microwave remote sensing. To calibrate the microwave radiometers is to establish a quantitative relationship between output (voltage or voltage digital) and input noise temperature. On-orbit calibration uses the calibration target of the sensor and the cold space as reference sources. It has been found that the performance of the same microwave instrument will be degraded with the aging components. Observations from microwave instruments of different satellite generations may be inconsistent, and with different systems the receiving radiance for the same atmospheric scene could be also different. To calibrate the microwave payloads onboard FengYun satellite, the calibration/validation is performed based on the global navigation satellite system (GNSS) retrievals, focusing on the sounding mechanisms of microwave and the GNSS occultation payloads on FengYun polar-orbiting meteorological satellites. For GNSS occultation data, the detection accuracy above 3 km is better than that of the microwave radiometer. Within the time window of 30 min and the spatial resolution of 0.5 degree both in latitude and longitude, the brightness temperature deviation is better than 3 K for clear sky. The results show that the FengYun meteorological satellite can not only provide global all-weather temperature and humidity profiles but also realize self-cross-calibration for microwave sounders with complementary instruments onboard.