Abstract: The feedback loop structure is and the core structure of dynamic changes in complex systems,and the analysis based on the feedback loop structure is the key to the specific management countermeasures of such systems. How to analyze the feedback loop structure and realize the effective feedback loop development management is an important problem to be studied deeply. In order to solve the above problems, a four-step analysis method of key variable correlation feedback loop is proposed:Firstly, the flow rate is established into the basic tree model of the complex systems by using the new branch vector determinant algorithm of system dynamics. Secondly, on the basis of the system development goal, the key variables are determined. Thirdly, the total feedback loop of the system is calculated by using the vector Algorithm, key variables associative feedback loop structure flow diagram are constructed, and determines the associative feedback loop structure flow diagram's dominant feedback loop is determined. Finally, according to the key variables leading feedback loop analysis, the management strategy is determined. By taking the system of Debang scale breeding and cultivating for example, the basic tree model of the flow rate of six trees is established including. According to the three major goals of system development, the three key variables including:aquaculture profit, annual application amount of organic fertilizer application, household pig manure annual output of biogas slurry are determined. Based on the construction of three key variables associated with the feedback loop structure, according to the development of Debang scale breeding system, combined with historical data of Debang aquaculture industry, biogas slurry development, household biogas digesters construction, the dominant feedback loop of three associated feedback loop structures is determined. Finally, according to the analysis of the dominant feedback loop, the three management strategies of the system development are determined. During the Practice of Management Countermeasures of Debon Scale Breeding System, the effectiveness of the three management strategies is verified, and the feasibility of this method in determining the complex system management countermeasures is verified. The four-step analysis method of key variable correlation feedback loop provides a normative method for feedback loop structure analysis, and also provide an operational process for the development of complex systems development management strategies.

Key words: correlation feedback loop, feedback dynamic complexity, scale breeding and cultivating system, system dynamics