Low Density Parity Check(LDPC) Codes is a class of approaching limits error correction codes which has gained widely application in communications. The excellent performance, however, is the result of a large number of repeatedly conducting iterative decoding algorithm, and is apt to be seriously affected by small girth in the parity check matrix. In this paper we present a novel serial concatenated scheme for LDPC codes which utilize much smaller generation matrix and the interleaver to reduce possibilities of girth, thus reducing the number of iterations in decoding. Simulation shows that the new codes have better performance while less requirement of iterations.