The variation rule of the sensitive physical properties of Al-16%Si alloy melt was studied. The results show that within a certain temperature range, the electrical resistivity of Al-16%Si alloy melt changes abruptly in the forms of inflection points or platforms, which is ascribed to the changes in the internal microstructure of the melt. Based on this rule, the variation characteristics of microstructure can be revealed. When remelting and overheating Al-16%Si alloy to 1050℃, the hereditary effects of different original structure on solidification structure after remelting can be eliminated, which can provide scientific foundation for properly controlling the hereditary factors transmitting the structural information of melt.