After surveying the research of MIMO (multiple-input multiple-output) multi-hop wireless networks, this paper analyzes the MIMO mechanisms for multi-hop wireless networks and discusses the effect of MIMO upon separate network layer and the whole design of multi-hop wireless networks. Focusing on cross-layer design, it expounds the fundamental mechanism of existing representative protocols and algorithms for MIMO-based multi-hop wireless networks, and compares and analyzes their characteristics, performance as well as deficiencies. Finally, by pointing out current research development, it summarizes the restrictions to the practical applications of MIMO-based multi-hop wireless networks, and proposes the importance of designing an adaptive and high performance cross-layer model which based on MIMO technology for multi-hop wireless networks.