Abstract: Within the framework of a unity feedback closed-loop control structure, a new analytical design method of decoupling controller matrix is proposed for multiple-input-multiple-output processes with time delays often encountered in chemical and industrial practice. Its dominant merit is that it overcomes the deficiency of existing methods based on numerical calculation and can realize significant or even absolute decoupling decoupling between the nominal responses of system outputs. Moreover, the adjustable parameters of the decoupling controller matrix can be tuned on-line in a monotonous manner to cope with the unmodelled process dynamics. At the same time, sufficient and necessary conditions for holding the control system robust stability are analyzed in the presence of the process additive and multiplicative uncertainties often encountered in practice, and correspondingly, the on-line rule for tuning the adjustable parameters of the decoupling controller matrix is provided. Finally, simulation examples are included to demonstrate the superiority of the proposed method.