Abstract: The resolution of polarimetric SAR (PolSAR) can be improved by using the conventional method to different polarization-channel data independently. However, it doesn’t exploit the polarization information entirely, which essentially presents the target scattering. In this paper, full-polarization data is decomposed according to Pauli’s basis. Under this decomposition, we develop a PolSAR bandwidth extrapolation algorithm, which is jointly extrapolating the frequency bandwidth of all polarization-channel data. By the joint extrapolation, the proposed method can obtain more accurate prediction model than the conventional bandwidth extrapolation method, yielding higher resolution. Experimental results of real data are presented to demonstrate the effectiveness of the proposed method.