The corrosion mechanism of three aluminum ingot mold materials used by Chinese aluminum electrolytic enterprises in molten aluminum was studied: The three materials are pearlite cast iron(PCI) contains vermicular graphite, lamellar graphite, and spherical graphite respectively. After 800 °C molten aluminum corrosion for 4 h, the intermetallic compound (IMC) layers of Fe2Al5 and FeAl3 is formed at the interface. It was found that the volume of spherical graphite in IMC was reduced to 20%, and lamellar graphite aggregated in the IMC layer. The average thickness of the Fe2Al5 layer in PCI1, PCI2 and PCI3 is about 180 μm, 100 μm and 101 μm, respectively. The weight loss rate of PCI1 is 2.57 (mg cm−2)min−1, PCI2 is 2.20 (mg cm−2)min−1, and PCI3 is 2.24(mg cm−2)min−1. There are dispersed Cr and Mo carbides in the IMC layer. Si-rich ribbon-shaped region was found at the interface between cast iron and IMC. The needle-like precipitates (Al4C3) were observed only at the only at the boundary between cast iron and IMC in PCI1.