<正> This paper firstly presents an algorithm of multivariable Nyquist predictivecontrol.Also,its relevant closed-feedback frame is proposed,by which the stability of thesystem can be immediately tested and the calculation of the algorithm is very convenient.Finally,the simulation of the predictive control algorithm to design a multivariable tem-perature control system for a 200MW thermal power unit is illustrated.The results of thesimulation show that the control system has good control performance.