Aiming at closed-loop water system, by the method that shutting certain subcircuit, and solving the piping network, computing flow deviation of other subcircuits, then analyzing the rules of variation of stability with various factors, following conclusions are obtained: When reducing the resistance in main pipes, increasing resistance of subcircuits, system stability can be improved. Centralized regulation by changing power has no influence on system stability; centralized regulation by changing resistances will decrease system stability. Pump characteristics curve influences system stability, stability of the flat characteristic is superior to the steep one. For direct return system (DRS), the stability of subcircuit which is farthest from the heat source is the worst. For reverse return system (RRS), the stability of subcircuit in the middle of the pipe-network has the worst stability. Overall, stability of RRS is inferior to that of DRS. Aiming at closed-loop water system, by the method that shutting certain subcircuit, and solving the piping network, computing flow deviation of other subcircuits, then analyzing the rules of variation of stability with various factors, following conclusions are obtained: When reducing the resistance Central regulation regulation by changing power has no system on instability; stability regulation of changing system stability, stability of the gradient characteristic system For reverse return system (RRS), the stability of subcircuit in the middle of the pipe-network has (DRS), the stability of subcircuit which is farthest from the heat source is the worst. the worst stability. Overall, stability of RRS is inferior to that of DRS.