In this paper, we propose a low complexity MIMO detection method for double space-time block (D-STBC) coded OFDM system. The proposed MIMO detector involves two step decoding process to efficiently de-correlate spatially-multiplexed / space-time-coded signals. The proposed MIMO detector collects feedback information from interfering spatial domain. Then, interference cancellation is applied once to reduce latency. A unique QR decomposition with partial maximum likelihood detection scheme is developed to lower computational complexity while performance is significantly improved. From computer simulation results, our scheme in D-STBC OFDM system outperforms previously proposed iterative detectors based on turbo equalization principle.