Greater than 1250 degrees. According to the query of ash melting point of coal, the ash melting point of Funing coal in Yunnan is greater than 1250 degrees, and the ash melting characteristics of coal are expressed by three characteristic temperatures when the coal ash changes from solid to liquid. The softening temperature represents the ash melting point of coal, and the ash melting point of various coals is1100 ~1600℃. Practice shows that when the softening temperature of coal is greater than 1350℃, slagging in the boiler is not great, and the outlet temperature of the boiler furnace must be controlled below the ash melting point 150℃ to avoid the flue.