Abstract: With the rapid development of Internet，various applications based on the Internet have emerged.The congestion control becomes a most important protocol which improves the Internet’s stability and robustness.Its development requires network to manage itself.The traditional end to end strategy can not solve all congestion problems.As a result of imprecise estimate on RTT，original REM is not able to accurately reflect the congestion state.Based on the cybernetics and REM algorithm，an improved AQM algorithm and a congestion control strategy are proposed.The simulation result shows that the new one can effectively decrease the packet loss rate and improve network performance.