Abstract: The air conditioning system in primary processing department with steam humidifier presents some problems,such as waste of steam and electric power and fluctuations of temperature and humidity during the turn of seasons from spring to summer or from summer to autumn.The humidifying system was improved with a high pressure cold atomizing system.A scheme integrating the control systems of high pressure humidifier and air conditioning system was proposed,the mutual relation between address in Mod bus and address in PLC S7-200 of humidifier was discussed for the implementation of centralized monitoring.The practical operation showed that the centralized monitoring system works stably and reliably,it cuts the running time of refrigerator,reduces the energy consumption of centralized air conditioning system by 5.702×10⁵ kWh and steam consumption by about 4500 t during the turn of the seasons from spring to summer or from summer to autumn.