Abstract: The polarimetric radar has the advantage of observing the target scene all-weather and day-night. It is widely used in many fields. As a multi-channel system, non-ideal factors such as crosstalk and channel imbalance between polarization channels can lead to the measurement error of the target polarimetric scattering matrix, which can further affect the scattering interpretation performance of the target. In this paper, man-made target as the research object, the influence of polarization measurement error on scattering interpretation performance is studied by using polarization measurement error model and coherent polarimetric target decomposition. Taking Krogager decomposition as an example, the analytical expressions of the decomposition components and measurement error sources of typical scatterers such as trihedral, dihedral, dipole and helix are derived, and the variation curves of decomposition feature parameters are given, revealing the influence mechanism of polarization measurement error on scattering interpretation performance. On this basis, the darkroom measured data of “pioneer” UAV are quantitatively analyzed. When Krogager decomposition error is less than 10%, polarization isolation is required to be less than -23 dB, polarization channel amplitude imbalance and polarization channel phase imbalance are less than 3 dB and 8.4°, respectively. The research work provides guidance for the parameter design of polarimetric radar system.