This paper defines a D-vector and D-matrix

based on which a new ensemble of LDPC code

called as D-LDPC codes

is developed.We discover that the D-matrix has the characteristics of orthogonality and circular-shift

by means of which we construct sparse parity-check matrix based on algorithm sequence.Studying shows that the D-LDPC codes has many advantages

such as the performance of the D-LDPC code is as same as

or in some extent

much better than convolution codes at the condition of middle and low code length and 1/2 code rate;the complexity of the algorithm to encode a D-LDPC code is

O(M)

which is lower than

O(N)

of the complexity for the convolution codes;the D-LDPC code has high flexibility concerning design of code length and code rate

which makes it compatible with the existed standard.