Abstract: The polarimetric calibration is a precondition and a foundation to accurately acquire the polarization scattering characteristics of radar targets.For the polarimetric radar systems,concept and classification of the polarimetric calibration are introduced.The development history of the polarimetric calibration techniques is summarized.The error model of the backscattering polarization scattering matrix measurement is analyzed.Several typical polarimetric calibration algorithms for point targets are concluded;various calibrators and limitative conditions for the typical algorithms are presented respectively;the advantages and disadvantages of the typical algorithms are listed;the polarimetric calibration capabilities of the typical polarimetric calibration algorithms are compared by the simulation when low,medium and high polarization isolations are considered respectively.The further research about the polarimetric calibration techniques is indicated.As the passive polarimetric calibration techniques for point targets can be widely used in the polarimetric calibration of the ground-based polarimetric radars and the polarimetric synthetic aperture radars,etc.The research of passive polarimetric calibration techniques has important value in theory and practical applications.