Although new energy technologies are developed rapidly, coal will still be the main energy source in China for a long timeto come. High calcium-iron coal is an important coal resource in China, which is widely distributed. Its ash fusion temperature TAF is lowand cannot be directly applied to entrained flow gasifier. Therefore, taking high-calcium-iron coal (MO) as the research object, high sil⁃icon-aluminum coal (Y4) was selected to regulate its ash fusion characteristics. The regualtion mechanism of ash fusion characteristicswas discussed by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy (Raman) and Fact⁃Sage thermodynamic software. The results show that with the increase of Y4 ratio, the TAF of the mixed ash sample increases gradually.When the mixing ratio of Y4 is 40%-50%, the flow temperature of mixed ash sample is 1 354-1 389 ℃ , which met the requirements forslag tapping of the entrained-flow gasifier. The XRD and FactSage results show that with the increase of Y4 content, the gradual disap⁃pearance of low melting point minerals and the formation of stable aluminosilicate minerals (like anorthite) mainly result in the increase ofTAF. From the three-phase diagram, it is found that with the increase of Y4 mixing proportion, the minerals in the ash sample changefrom melilite to anorthite. FT-IR results show that with the increase of Y4 ratio, the Si—O in the ash sample moves to the high frequencyregion, and forms a broader absorption peak between 900-1 000 cm-1. Combined with XRD result, it is judged that the absorption peak isanorthite. From the perspective of silicate melts, the parameter R is introduced to represent Si—O—A. With the increase of Y4 content,the R in the ash sample increases in a " stepped" pattern, leading to an increase in network polymerization degree, which explains the in⁃crease in TAF.