Regarding the morphology of alumina, effect of the heredity of raw materials on properties of alumina-magnesia refractory castables was investigated by adding platelet alumina as the specific template. Inª²situ spinel platelet formed derived from platelet alumina. By comparing phase evolution, apparent porosity, bulk density, permanent linear expansion and strength, it was demonstrated that the utilization of the microstructures’ heredity of platelet alumina was a new alternative for controlling properties of alumina-magnesia refractory castables.