Due to the MAC (medium access control) protocol, routing protocol and TCP itself, the TCP flow is very unstable in the wireless Ad Hoc networks based on IEEE802.11. However, the main reasons that make the TCP flow unstable are the unfairness of MAC protocol and the false link failure message that causes the long route discovery procedure. Combining with the IEEE802.11 MAC protocol and DSR routing protocol, these causes are analyzed in detail and the enhanced algorithm to IEEE802.11 MAC protocol and DSR routing protocol is given in this paper. The simulational results show that the proposed algorithm can ultimately avoid the instability of TCP flow and increase its average throughput in the wireless Ad Hoc networks.