Abstract: To improve performance and reliability of control system in coal preparation plant of China coal group Shanxi golden ocean energy Co Ltd,centralized control system is designed on the basis of NA400 series PLC; this paper introduces component,function,and technical characteristic of this system as well as analyzes its application. The application shows that this system is more reliable and performance is better; it can centralized control equipment for coal handling and washing in each remote substation as well as offer general assessment of production,operational condition of equipment,alarming information and capacity etc.