Abstract: A 2-level hierarchical and intelliget control, knowledge based scheme are proposed for 4-juxtaposed boilers. In the execution stage, a knowledge - based self-tuning control and selfoptimizing control scheme is achieved for the combustion process of the boiler. In the coordination stage, the optimization of boiler-load and centralized management of the whole system are implemented. Actual running of the unit has shown that the combustion efficiency can be increased 4.7%. Under conditions of significant fluctuations in steam-load and conditions of combustion in the boiler, the automatic control system can assure better adaptability and reliability. In addition, the system can be regulated conveniently.