The process of continual carbonation decomposition is a long time-delay and strong-coupling complex industrial process, and it is difficult to be controlled by traditional method. Based on the principle knowledge and experts' experience an expert control system for the process of continual carbonation decomposition was developed in this paper. Expert rules which consist of optimization control rules and safety supervising rule were expressed by production-rule. The forward-feed method was adopted to compensate the effect caused by the fact of long time-delay. The practical results showed that eligible ratio of decomposition ratio increased by 4%, and average value of decomposition ratio was up to 94.2%