The space time spreading,superimposed training sequences,and space-time coding are used to present a multiple input and multiple output(MIMO)systems model,and a closed-form of average error probability upper bound expression for MIMO correlated frequency-selective channel in the presence of interference(co-channel interference and jamming signals)is derived.Moreover,the correlation at both ends of the wireless link that can be incorporated equivalently into correlation at the transmit end is also derived.which is significant to analyze space-time link algorithm of MIMO systems.