Construction method of LDPC check matrix and LDPC encoder

The invention relates to the field of communication, and provides an LDPC check matrix construction method and an LDPC encoder. The method comprises the following steps: dividing a check matrix into a front check part and a rear check part; the row weight rw of the inverse matrix of the post-verification part is determined, n nodes are randomly selected from the inverse matrix of the post-verification part, values corresponding to the selected n nodes are calculated, and n = rw-2; setting a value corresponding to an adjacent node of one of the selected n nodes as a zero array and calculating a residual value of the row; calculating values corresponding to the remaining rows to obtain all values of the inverse matrix of the post-verification part; and constructing the check matrix according to all value combinations of the inverse matrixes of the pre-check part and the post-check part. According to the method and the device, the structured LDPC check code suitable for the high code rate environment can be cons