Abstract: Based on the study of the Water Plant Control, this paper stadies the optimal control problem of a kind of Large-Scale System with disturbances and its subsystems are interconnected by a Delay Dynamic Process. An Adaptive Hierarchical Control Method with Dual Feedback is advanced, which not only can meet the requirement of constraints and improve the performance index as closed-loop control but also requires fewer computational effort and has a good convergence as open-loop control. The estimation of the "Connecting Process Model" even further improves the control. Similation shows its convergence and effectiveness.