The relationship between the properties of the composite and the addition of the preventing crack additives, dispersion agent, SiC, graphite, stainless steel fiber have been researched. Finally, alumina-based composite materials used for prefabricated iron runner with better ratio of properties and price has been developed by the studying of the properties and microstructure of alumina based composite materials. The best composition for the iron line is Al 2O 3-14%SiC-5%G-4%SiO 2-2%micropoeder-1%white clay-6%cement;the best composition for the slag line is Al 2O 3-16%SiC-5%G-4%SiO 2-2%micropoeder-1%white clay-6%cement;addition of both is 0.15%Na 5P 3O 10-3B aluminum powder-2%stinless steel fiber. The mechanism on the composite materials eroded by molten iron has also been discussed.