In this paper, a binary serial turbo LDPC code is presented. It represents a serial concatenated LDPC codes separated by interleavers, with iterative decoding. In this work, we aim to investigate the performance evaluation of concatenated code, with reduced complexity and decoding delay, associated with high order constellation using Gray mapping, over Gaussian and Rayleigh channels. Simulation results show that the performance of a serial concatenated LDPC codes is higher than that of single LDPC code with the same code rate and code block length.