The invention provides an orthogonal intersection amplitude modulation signal phase ambiguity processing method and apparatus. The phase ambiguity processing method comprises steps of judging symbols in the X polarization state and the Y polarization state of a reception signal, and carrying out mapping to obtain first bit information, wherein the reception signal comprises multiple first signals; carrying out verification analysis of the first bit information to generate a first verification result; judging the first verification result to obtain a judgment result that whether phase ambiguity occurs to the reception signal or not; when the judgment result shows that phase ambiguity occurs to the reception signal, obtaining at least one first signal in the reception signal; subjecting the first signal to phase rotation to obtain a second signal; carrying out verification analysis of the second signal, storing the second signal if the verification result is normal, and enabling the second signal to be used for decoding instead of the first signal. In the verification of the QAM signal, the QAM signal is corrected when phase ambiguity exists, so that the error rate of QAM signal differential decoding is lowered, the system expense is reduced, and the system performance is improved.