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The microwave radiation data of the earth"s surface and atmosphere observed by the spaceborne microwave radiometer are basic source for numerical weather prediction and climate research. Due to the difference of the response characteristics and of the calibration absolute reference between each sounder and variation of the on-orbit working conditions, there are certain bias between the data of different or the same radiometers over a long period of time. If these biases are not corrected, it will have significant implications for long time series applications (such as climate studies), and may even lead to erroneous results. In addition, it is impossible to perform absolute calibration of onboard data since the absolute reference for calibration is not clear. So it is necessary to use other relative calibration methods to evaluate the stability and variation characteristics of the radiometer. In this dissertation, in order to adjust the calibration biases, a correction model for the calibration biases of the microwave humidity sounder is established considering the principle of system responses and on-orbit calibration, which is also called re-calibration methods, based on OMB technique (observed brightness temperature (O) minus simulated brightness temperature (B)). Using the re-calibration methods, L1 level observation data of the FY-3C microwave humidity sounder was analysed and the re-calibration coefficients were calculated. Then, using two data sets, the re-calibration coefficients were verified. The residual and validation results show that the time series of recalibration results is stable, and some abnormal fluctuations in the original OMB biases have been well corrected after re-calibration, this means that the re-calibration methods is valid. And the method is based on the system responses of microwave humidity sounder, therefore, it is also applicable to other FY-3 series satellite microwave humidity sounder for calibration biases correction. When using the same radiative transfer (RT) model, this re-calibration methods can achieve consistent calibration of FY-3 series satellite microwave humidity sounder data.