The weighted multiple-model adaptive control (MMAC) has been sucessfully used for single-input single-output (SISO) systems,but for multiple-input multiple-output (MIMO) systems,satisfactorty application results are still quite few.The weighting algorithm designed for SISO systems could not work well on MIMO systems.In the paper,two different weighting methods,namely,the scalar and vector weighting algorithms were considered and their effectiveness were verified through Matlab simulations.The weighting algorithms' parameters were adjusted in order to quickly recognise the change of system parameters.Different error performance index has influence on the convergence speed of the weighing value.Through Matlab simulations,it is found that the scalar weighting algorithm with constant coefficient error performance index mentioned in the paper can achieve an ideal control effect on MIMO systems.