Abstract: Effects of water transfer engineering on the ecology of the Tarim River were analyzed,exposing principles and characteristics of the feedback mechanism of the ecosystem,particularly negative feedback of the ecosystem,i.e.while an ecosystem is subjected to external impact or disturbance,it will initiate a series of autoregulation functions to alleviate intensity of the impact or disturbance in an attempt to restore its balance or stability.Moreover,effects and significance of the feedback mechanism of an ecosystem has been explored.

Key words: human activity , ecosystem, feedback mechanism, Tarim River, ecological water demand, entropy, coupling