Abstract: In order to realize automatic ball-adding for Huibaolin Iron Plant，Shandong Linyi Mining Group，a set of ball-adding fuzzy control system based on real-time shaft power detection of ball mill was designed，according to former worker's practical experience and expert knowledge in ball-adding.The control scheme，system composition，fuzzy language variables and its fields determination，determination of fuzzy control rules，the inverse fuzzy output and PLC system are introduced.After the fuzzy system was put into use，well running effect were obtained.It kept running current of ball mill smoothly and steadily，reduced energy consumption and improved grinding efficiency.

Key words: Ball mill, Automatic ball-adding, Fuzzy control