The wireless communication is highly affected with the channel behavior. The uses of multiple-input multiple-output system and FEC code are most common in wireless standard for provide the fast and reliable communication. In this paper, Space-Time Block Coding (STBC) for Multiple-Input Multiple-Output (MIMO) set-up is used in wireless channels. In the special version of STBC called Alamouti code is used for exploiting the performance of MIMO in Adaptive modulation. The further improvement in error rate has been achieved using turbo code. The simulation of the system has been analyzed for different modulation schemes. The comparative result has been given in this paper.