Abstract: In order to understand the slagging properties of blended coal, different coal blending and flux agent were added to Jincheng anthracites. The X-ray diffraction (XRD), thermodynamic software FactSage and ash fusion temperature (AFT) test were employed to analyze the ash fusion characteristics of blended coals and the mineralogical properties of the blended coal ashes. The results show that the content of ash in coal has an important role in the AFT change of blended coals. The lower the ash contained in raw coal is, the easier the AFT of blended coal lowers. The addition ratio of coal blending is 20% and 30% when the AFT decreases significantly for coal C with low ash content and G with high ash content, respectively. There is more significant fluxing effect of K on C than that on G. It is found that the feldspar mineral is formed at the deformation temperature. The decreasing in contents of mullite as well as the appreciably increasing for feldspar is the main reason for the decreasing of AFT. The thermodynamic analyses indicate that the producing of liquid matter is related to the rapidly decreasing in the contents of anorthite and quartz, as well as slowly decreasing for mullite at high temperature. The anorthite takes part in the formation of liquid matter. The fluxing effect of anorthite depends on the contents of matter which can react with anorthite to produce a melt with lower fusion point.