Abstract: The sinter is consolidated by fluid liquid phase through adhering the adjacent not-molten materials, and the fluidity of liquid phase is a sintering basic characteristics of iron ore. Two new evaluation indexes, the liquid phase fluidity area based on temperature distribution (FAT) and the index of sensitivity of fluidity to temperature (ISFT), were proposed. Their corresponding calculation formulas were given to rightly master the action of liquid phase in sintering and optimize ore-matching.