Boilers are important power equipment in petroleum, electric power, chemical industry and other industries. Today's social resources are strained and environmental damage is becoming more and more serious. Therefore, as a device that converts primary energy into secondary energy, boilers play an extremely important role in the process of centralized heating. The utilization of resources reduces environmental damage. In this paper, the boiler drum liquid level is researched, and the automatic control of the boiler liquid level is realized by a combination of frequency converter, industrial computer and PLC control. Through the application of fuzzy control, the steam boiler drum level control can be better achieved, and the control effect has been greatly improved in terms of static stability and dynamic stability.