Nowadays, entrained flow bed gasification technology is the foundation of the modern coal chemical industry, while its liquid slag discharge process generally requires the flow temperature (FT) of coal ash to be less than 1400 degrees C. To reduce the ash fusion temperature (AFT) of high AFT coal and to make full use of the direct coal liquefaction residue (DCLR), Jincheng coal (JC) with a high AFT and Shenhua DCLR with a low AFT are used to prepare blended samples. The influence of the DCLR on the AFT of JC is explored using an intelligent ash fusion point tester, ternary phase diagrams, differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results show that the addition of DCLR can reduce the AFT of JC effectively; when the amount of DCLR added is higher than 25%, the FT of the mixed coal ash is lower than 1400 degrees C, which meets the requirement of a liquid slag discharge process. The back propagation (BP) neural network prediction model based on the FT data of partial coal blending ratio experiments has a better prediction accuracy than empirical formulas. The results of DSC show that the heat capacity of blended coal ash varies significantly ranging from 1000 to 1300 degrees C; at the same time, the results of XRD and SEM also show that a series of chemical reactions among ash compositions of blended coal happen between 1000 and 1200 degrees C. The chemical reactions mainly include the decomposition of CaSO4 into CaO and the reduction of Fe2O3 into FeO. Meanwhile, CaO and FeO react with SiO2 and Al2O3 to produce a series of new calcium/iron-containing aluminosilicates (anorthite (CaAl2Si2O8), fayalite (Fe2SiO4), hercynite (FeAl2O4), etc.), and CaO and FeO in coal ash have a significant inhibitory effect on the generation of mullite (Al6Si2O13). FeO in coal ash can easily form glassy state substances and cause the sintering of coal ash. The reason for the higher AFT of JC is that its ash contains a large amount of Al6Si2O13 at high temperatures, and the reason for the lower AFT of the DCLR is that its ash has a large amount of calcium/iron-containing aluminosilicates, especially rich in a large amount of gehlenite (Ca2Al2SiO7). In addition, the calcium/iron-containing aluminosilicates in coal ash have a certain positive synergistic effect on the reduction of FT.