Abstract: Ten Huainan coal ash samples with different ash fusion temperatures were selected. To calculate the flow temperature by using the typical empirical formulas based on ash chemical composition and the new approaching were conducted. The composition of crystal mineral in ashes was analyzed by using XRD combined with "Value K" method, and the relationship between crystal mineral composition and the flow temperature was determined. An available formula for predicting the coal ash flow temperatures based on the crystal mineral composition was proposed. It is found that the typical empirical formula has a big error for predicting, but the difference between experimental value and calculated value by proposed formula is less than 80℃ required by China National Standards.