Abstract: The dosing of reagent in flotation of fine slime is generally made under manual control at coal preparation plants. This dosing method relies heavily on experience of operators, and is high in labor intensity and uneasy to control and maintain steadiness of indices of products, causing consequently the waste of reagents or loss of flotation concentrate. To deal with these issues, an intelligent control system is proposed based on online measurements of flotation process parameters as well as the characteristics that the flotation process is subjected to the influence of multiple factors. The system is comprised of two parts — the intelligent reagents dosing system developed by inference to the result of case study and the two-way intelligent flotation process control system based on indices of products. The system has been used at Handan Plant for remoulding the flotation process. Field application shows that the intelligent online ash meter can execute measurement of ash of tailing within 3 minutes with a measuring accuracy within 1.9%; the reagent can be steadily added with a drop of consumption by 5 percentage points compared to the previous figure before the use of the system; the flotation process can now be proceeded under intelligent control, and quality of concentrate can be stabilized, leading to a rise of yield of concentrate by over 0.3 percentage point compared with the previous figure; the labor intensity is much lessened.