In this paper, we will use the Space Time Block codes for antenna diversity, and the performance of Space-Time – Turbo Trellis Coded Modulation (ST-TTCM) is investigated over Nakagami channels. For high data transmission over wireless fading channels, Space-Time Block Codes provide the maximal possible diversity advantage for multiple decoding algorithms. The effects of fading channel are considered and modeled by Nakagami distribution function. Here, we investigate Space Time- Turbo Trellis Coded Modulation (ST-TTCM) for 8PSK for several Nakagami parameters M. Thus, our results will reflect the degradations both due to the effects of the fading on the amplitude of the received signal.