To investigate the corrosion behavior of the clay-bonded kaolin chamotte by molten aluminum, the mixture of 20 wt% fire clay and 80 wt% kaolin chamotte was prepared and fired in the temperature range 900~120$0^{circ}C$. The specimens fired at each temperature were reacted with molten aluminum at 90$0^{circ}C$. The results obtained in this experiment are as followed. 1) It was confirmed through X-ray diffraction analysis that the clay-bonded kaolin chamotte exposed to molten aluminum suffered penetration by the reaction of aluminum with silica forming alumina and metallic silicon. 2) Penetration was independent whether the silica existed as free or one component of mullite. 3) Penetration of the specimen fired at 90$0^{circ}C$ was negligible while the others fired above 100$0^{circ}C$ showed remarkable penetration. 4) Penetration rate at 90$0^{circ}C$ was parabolically increased with the holding time as in the case of metal oxidation.