The existing LDPC code open set recognition algorithm uses the code length and the starting point of the code word as known conditions for recognitionwhich limits the practical application of the algorithm.In order to overcome this shortcomingthis paper proposes a code length and code word starting point recognition algorithm based on the minimum error judgment criterion.Firstthe received sequence is intercepted according to the estimated value of the code length and the code word starting point to construct a code word analysis matrixand then Gaussian column transformation is conducted on the analysis matrix and possible check vectors are obtained.The LDPC code check vector is further selected based on the minimum error judgment criterionand finally the maximum number of check vectors at different traversal values of code lengths and code word starting point is foundso as to realize code length and code word starting point identification.The simulation experiment results show that when the bit error rate is on the level of 10-3the recognition rate of the algorithm reaches 100% for the LDPC code under the IEEE802.16E protocol.