Abstract: Concatenated space-time code is one of the efficient encoding that can improve the error correction capability and approaching the Shannon limit. The performance will be greatly enhanced when channel coding and space-time coding combination used, thus the concatenated space-time code becomes one of the important direction in space-time coding research. In this paper, the RS code and LDPC code concatenate scheme with space-time code were introduced, and the bit error rate characteristics under different atmospheric turbulence condition were analyzed. The results show that the concatenated spacetime code can significantly improve the performance of the MIMO system, inhibit atmospheric turbulence effects, conducive to obtain coding gain and further more improve the system BER performance.