Aiming at the problems of poor fault tolerance and low recognition rate of the existing LDPC code verification vector recognition algorithms, an iterative recognition algorithm for LDPC code verification vector is proposed. Firstly, the probability distribution of the log-likelihood ratio of the parity relation is analyzed by using the soft information of the channel output, and a pre-decision method of the parity vector is found. The theoretical values of the pre-decision threshold and the size of the data matrix are deduced, which greatly reduces the search space for constructing the parity vector. Then, under the condition of soft decision, using the generalized logarithmic likelihood ratio, the vector in the search space is judged and the check vector is obtained. Finally, multiple sets of data are used to iterate to find the check vectors in the search space. Experimental results show that compared with the existing algorithms, the vector search space of the proposed algorithm is greatly reduced, and the recognition rate is also significantly improved in the low SNR environment. Moreover, the decoding gain of the algorithm is increased by about 2.3 dB.