For the dehydrogenation of ethylbenzene to styrene，a predictive functional control algorithm was presented. The robust stability conditions of the closed-loop system quantitatively based on Lyapunov function was provided to assure the stability of the designed closed-loop system. Furthermore，the presented algorithm was applied to a styrene unit，in which ethylbenzene feed，outlet temperatures of furnace A and furnace B，steam flowrate，inlet pressure of compressor were manipulated variables，and the conversion rate and selectivity of the process of dehydrogenation of ethylbenzene to styrene were controlled variables. Despite perturbation，the simulations showed that the presented algorithm could guarantee the conversion rate in an expected range，which was attributed to the stability of production.