Multipath jamming is an effective self-defense jamming mode used to counter airborne fire-control radar or radar seekers. Multipath jamming has a deceptive jamming effect on the range, velocity, and angle of radar, making it difficult to identify and suppress. In this study, a polarized radar seeker structure is proposed. Based on the mechanism of the multipath jamming effect on radar, orthogonal polarization signal models of jamming and direct arrived signal are established. Next, a method to detect multipath jamming based on statistical property differences of polarization phases is proposed. The physical connotation of this method is clear and easy to realize. This method can be used to determine the presence of a jamming signal and identify the signal pattern and polarization types. The feasibility of this method has been verified via a simulation experiment, thereby demonstrating that the method serves as a useful reference for effectively countering multipath jamming.