Abstract: Aiming at the problems of serious overgrinding，high energy consumption and limited im⁃ provement of iron concentrate quality in the third stage ball milling system of a concentrator in Inner Mongo⁃ lia，the grinding experiment of nano-composite ceramic balls instead of steel forging was carried out. By sys⁃ tematically comparing the grinding technical efficiency and product particle size composition of ceramic balls and steel balls under different ball loading systems，filling rates，grinding concentrations，and time conditions，it was concluded that the qualified particle size(-0.075+0.018 mm) yields of steel balls and ce⁃ ramic balls were 62.74% and 63.02%，respectively. The grinding technical efficiencies of steel balls and ce⁃ ramic balls were 69.28% and 70.46%，respectively. The qualified particle size yield rate and grinding tech⁃ nical efficiency of ceramic balls were higher than those of steel balls. The comparison of magnetic separation effect of different media grinding products and ball consumption and energy consumption in grinding process shows that the iron grade of ceramic ball magnetic separation concentrate is slightly higher than that of steel ball grinding，and the content of harmful impurities in ceramic ball grinding magnetic separation concen⁃ trate is lower. Under the same conditions，ceramic ball grinding can obtain better quality iron concentrate. The energy consumption and power consumption of ceramic ball grinding are lower than those of steel ball grinding，and the effect of energy saving and consumption reduction is remarkable. Nano-composite ceram⁃ ic balls have good applicability in fine grinding of iron ore，which can provide technical reference for high�efficiency and energy-saving grinding of similar ores.