The invention discloses a positive and negative slope LFM waveform orthogonal polarization radar-based anti-shift frequency interference method. The method includes the following steps that: (1) an orthogonal dual-polarization radar transmits signals in a positive and negative slope LFM waveform form, receives echo sequences, carries out matched filtering and normalization on the sequences so as to obtain the output sequences of an HH channel, an HV channel, a VH channel and a VV channel, and carries out time-domain reversal on the output sequence of the HV channel and the output sequence of the VV channel; (2) the output sequences of the four channels are processed, so that a sequence 1 can be obtained; (3) target detection is carried out on the sequence 1, so that target positions to be determined are obtained, a sequence 2 is extracted from the sequence 1; (4) the output sequences of the four channels are processed according to the target positions to be determined, so that a sequence 3 can be obtained through extraction; (5) the ratio of the sequence 3 to the sequence 2 is calculated and is adopted as an identification quantity; and (6) the identification quantity is compared with a threshold value, so that a target and frequency shift interference can be judged. According to the method of the invention, processing of signals which have been subjected to matched filtering does not involve complex operation, and therefore, the method has high real-time performance.