Abstract: In order to release the shortage problems of the coking coal resources in China and to improve the coal uillization efficiency, talking the heave medium middlings from Huaibei Coal Preparation Plant as a study object, a systematic study was conducted on the mineralogy features of the coking middlings.The X-ray diffrac tion and the scanning electron microscope were individually applied to analyze the phase composition of the coal samples and the mineral dissemination features of the different density coal samples to determine the rational crushed particle size.The liberation degree of crushed products was analysd.The results showed that the minera Is in the coking middlings would be clay mineral mainly.The analysis on the liberation degree of the crushed products with the scanning electron microscope showed tha t the coal samples crushed t0-0.5 mm could have a good liberation effect.With the progressive released floatation experiment, cleaned coal with production rate of 22.0 5% and ash content of 12.93% could be obtained.