Abstract: To overcome the difficulty in calculating the maximum output and optimizing the operation of a MPS-HP-II medium-speed coal mill, a calculation method was proposed for the new type of mill, and subsequently the calculation results were compared with actual experimental data. Operating conditions suitable for the coal mill were put forward through studies on its operating characteristics, during which the effects of primary air volume, separator baffle angle, mill output and loading force on both the pulverized coal fineness and the unit consumption were obtained. Results show that via the proposed method, the mill output can be accurately calculated, which, however, is still limited by drying output in the case high moisture coal is pulverized.