To identify the interference of polarization-modulated false targets generated by the forwarding of Digital Radio Frequency Memory (DRFM), a method of identifying polarization-modulated false targets is proposed.Firstly, a polarization measurement model of the circularly polarized antenna array based on time-space joint domain coding is proposed, and it is proved that this model can accurately obtain the polarization information of echoes after pulse compression.Secondly, according to the principle of the tensor product signal reception model of the polarization radar, the distribution difference between the target echo and the polarization-modulated false target echo in the four-dimensional complex space is obtained.Finally, based on the difference and in combination with the maximum and minimum distance algorithm and the density method, the K-means algorithm is improved, and a classifier taking the optimal clustering number K as the polarization discriminant quantity is designed.The simulation experiment takes 64 transmitted pulses as examples, and verifies that the proposed method has good discriminating effect under different Signal-to-Noise Ratio (SNR) and Jamming-to-Noise Ratio (JNR), and can effectively discriminate between targets and polarization-modulated false targets.