Abstract: Processing parameters during the preparation of ultra-fine calcinated coal kaolin powder were studied by using wet stirred mill. The results show that grinding concentration, time, the content and charge ratio of grinding media, stirring velocity of peddler are the important processing parameters of preparing ultra-fine calcinated coal kaolin powder. When the feed particle size is 100% minus 10 μm, ultra-fine powder which the particle size distribution is 95.5% under 2 μm, d₅₀ 0.97 μm is acquired by optimizing the processing parameters of stirred mill.