Abstract: Ash flow temperature (FT) is an important index for coal gasification, determining the slagging model of coal-combustion and gasification process. On the basis of flow temperature of 181 coal ash samples, the FT prediction model associated with ash composition and acid/basic ratio was set up. The correlation coefficient is 0.934, indicating the FT prediction values is in good agreement with the experiment values. The liquidus temperature was calculated by FactSage software. The formula between FT and the liquidus temperature was established, and the correlation coefficient is 0.924.