The invention discloses a cross iteration method for recognizing relay protection information. According to the method, cross iteration is carried out on feature codes of an information samples fed bya relay protection device to divide the feature codes into two stages; the feature codes which undergo cross iteration in the second stage are formed by deletion on the basis of the feature codes which undergo cross iteration in the first stage; and when completely matched feature codes occur in the cross iteration process of the feature codes in the first stage, data bits of binary numbers of the other feature codes are shortened according to a strong association relationship between the completely matched feature codes and the other feature codes, so as to form new feature codes, and in thesecond stage, cross iteration is carried out by adoption of the new feature codes formed in the first stage. According to the cross iteration process, the convergence speed of the cross iteration during the relay protection information recognition can be improved.