In order to reduce the effects of interference polarizations on sidelobe cancellation system, this paper proposes an antijamming method in spacepolarization domain based on dual polarization auxiliary antenna and Kalman filter. The paper transforms the auxiliary antennas into dual polarization and selects the polarized signal by auxiliary channel power, and then uses the Kalman filter and the selected signal channel to cancel the sidelobe jamming in main antenna channel . In this method, the side-lobe canceller system is regarded as error prediction filter; the optimized auxiliary channel output is weighted and added as the measurement; the weight vector is modified iteratively to reduce the error of the measurement and main channel signal, eliminating the side-lobe interference and improve the signal-to-noise ratio of main antenna channel. The simulation results show that the convergence speed and stability of this method are better than that of the conventional side-lobe cancellation algorithm, and the method applies to multichannel. The output SNR of orthogonal polarization interference is better than that of the conventional SLC of about 10 dB, and the stability is fine with low sampling points.