Efficient bi-directional multi-hop wireless networks based on MIMO algorithm or network coding have been proposed in recent papers. This paper proposes a new technique named as MIMO network coding, that is a combination of network coding and MIMO algorithm for multi-hop relay networks. By using MIMO network coding, co-channel interference cancellation and efficient bi-directional transmission can be realized simultaneously with lower complexity in multi-hop networks. Moreover, Space Time Block Code (STBC) MIMO transmission is also introduced to achieve higher reliability in MIMO network coding. It is confirmed from numerical analysis that the MIMO network coding with STBC achieves higher capacity and reliability than conventional schemes.