WiFi-MESH wireless network which are mainly based on the 802.11 protocols are developed quickly in recent years. The principle features, difficulties, directions and application schemes of the key technologies of WiFi-MESH systems, including MAC mechanisms and routing protocols, are analyzed and discussed. It can be concluded in the paper that the TDMA mechanisms based on 802.11 should be developed further for avoiding the collisions in essence, and the new BATMAN-adv routing protocol based on OSI architecture layer two may raise the performance of the systems more significantly than the HWMP routing protocol. Finally, some new technologies which could be used in WiFi-MESH are discussed.