Due to the randomness of the initial phase of the vector network analyzer, there will be a large error when the polarization characteristic parameter H/ α — is measured by using it. In this paper, a method of measuring and calibrating the full polarization scattering matrix by using vector network analyzer is proposed to obtain the polarization characteristic parameter H/ α — . Firstly, the measurement system of the full polarization scattering matrix is constructed, then the polarization scattering matrix is calibrated by the disk, 0° and 22. 5°dihedrals. Finally, the error caused by the randomness of the initial phase of the vector network analyzer is eliminated, and the accurate measurement of the polarization characteristic parameter H/ α — is realized. The results show that the error of the scattering angle α — obtained by polarization calibration is less than 3 degrees compared with the theoretical value, which indicates that the polarization characteristic parameter H/ α — of the target can be accurately obtained by measuring and calibrating the amplitude and phase of the polarization scattering matrix.