Abstract: In view of existing defects of PLC control system used in cement batching production line of a cement plant, such as many connections, long distance, many fault points and so on, the paper proposed a reform scheme of cement automatic batching system based on Profibus-DP, and introduced design of the system's hardware and software in details. The system takes Siemens S7-300 PLC as main controller, which has functions of running condition monitoring, unusual running warning, running parameter revision, real-time data automatic production and inquiry or printing of historical data's report.