The development processes of a new material, multi-component white cast iron, which contains several strong carbide forming elements and their special carbides with very high hardness, for roll in hot finishing stands, by researching it totally from the view points of alloy designing, solidification structure and solidification sequence and phase diagram, and phase transformation behavior and heat treatment characteristics are shown in this paper. As the results, the solidification structure, particularly type and morphology of eutectic carbides, could be controlled in a wide range by combination of alloying elements. Phase transformation behavior, obtained from the continuous cooling curves gave useful instructions to the heat treatment process. The hardness and retained austenite in matrix could be widely controlled and the remarkable secondary hardening due to precipitation of special carbides was found to make the matrix hard and strong enough for practical use. The