In order to realize optimization of coal crushing for coal blending,6 single kinds of coals and 2 kinds of blended coal were screened for preparation of different sizes distribution i.e.>3 mm,3~1 mm,1~0.5 mm,0.5~0.1 mm,and <0.1 mm.Analysis was made for the coal sample of each graded component in ash content,sulfur and G value.Compared with conventional coal indexes,study was done for different coal kinds,different screening gradation of different coal quality.The correlation between the fineness of each coal and HGI was also studied.The results show that HGI has a good correlation with the fineness of cleaned coal.The ash content of each coal showed a trend of first decreasing and then increasing with the decrease of grain size,while the sulfur content showed a trend of gradually increasing,and the caking index of each coal was slightly different.The trend of ash content of each grain size component of mixed coal is consistent with that of single coal,but the sulfur content and G value are not.