System dynamics method is based on feedback control theory, computer simulation technology as a means, generally used to study the quantitative method of complex systems. System dynamics will be divided into several interrelated system S subsystem, subsystem is composed of basic unit and A first order feedback loop, the first-order feedback loop contains state variables (L), rate (R) and (A) the basic variables, such as secondary variables can separately by the state equation, velocity equations and the auxiliary equation, said sometimes express equation in table function. The components of a system are based on causality, which determines the internal workings of the system. After describing the relationship of all the components of the system in the form of equations and parameters, the dynamic behavior of the system is analyzed with the help of computer simulation technology and the development trend of the system is predicted. Compared with other methods, the flexibility of system dynamics method is "building block" characteristics, the reaction is described, the cause and effect in internal system is dynamic, and simple and intuitive reflect the behavior of the system, is suitable for the analysis of dealing with complex social and economic problems, research on regional water environment carrying capacity, the including resources and environment and social economy, a large number of complex factors as a whole, comprehensive factors, considering the mutual relationship, and through the simulation of water environmental carrying capacity of regional dynamic calculation, from the viewpoint of system development, has the advantages of the model is intuitive, fast analysis speed.

Because system dynamics has great advantages in analyzing and solving many nonlinear complex giant systems such as social, economic and ecological environment, it has been accepted by many scholars around the world and introduced into their own research fields, and is known as a laboratory of practical systems.