A novel iterative receiver for multiple input multiple output (MIMO) systems was introduced.Its basis concept is that the reliability of extrinsic information will be strengthened with continuous iterations.Extrinsic information of present iteration is added with prior information of last iteration to obtain performance gain.The simulation results show that the improved iterative receiver can approach the 5th iteration performance of conventional soft interference cancellation (SIC)-minimum mean square error (MMSE) iterative receiver after the 2nd iteration with less computational complexity.Compared with conventional iterative receiver, the improved iterative receiver has 1dB performance gain at bit error rate (BER) of 10-5, with four transmit antennas and four receive antennas system.