Abstract: This paper presents a high-speed digital simulation method--the convolution summation method by using the blockpulse responses of the multivariable linear time-varying systems to obtain the time domain responses and objective functions of the systems. For calculating optimal control functions of the systems, each control function is expressed as a polynomial and the term number of every polynomial is expanded automatically by means of a program. Thus, the speed of optimizing the control functions is expedited and the total computer time is saved.