In order to improve the accuracy of channel estimation in MIMO space-time communication system, a turbo channel estimation which employs MAP iterative algorithm is proposed. The estimator utilizes the soft-decision information at the output of SISO channel decoders to iterative estimate the impulse response of MIMO channels. Since the STBC decoder depends on the output of channel estimator, the proposed method ameliorates the performance of STBC decoder. Simulation results demonstrate the superiority of proposed method at the performance of BER in 3GPP’s wireless channels.