When multiple parameters jump simultaneously, a multiple models adaptive decoupling controller using Dimension-By-Dimension technology is presented to solve the problems such as too many models, long computing time and so on. To find the optimal parameter, it adopts one-dimension optimization method in series instead of multiple-dimension optimization method in parallel. At any time only one parameter is focused to find the optimal value and other parameters are kept constant, which can reduce the number of the system fixed models greatly. According to the switching index the best model is chosen and the controller is designed accordingly. By the choice of the weighting polynomial matrix, it not only places the poles of the closed loop system arbitrarily, but also decouples the system dynamically. At last the global convergence is obtained. In the simulation example, if the same number of the fixed models is used, system transient response and decoupling result are improved greatly.