The invention discloses a method for refining, metamorphosing and casting cold roll steel by casting instead of forging. A work roll sleeve or a work layer of the cold roll steel comprises the following chemical components in percentage by weight: 0.6 to 1.2 percent of C, 0.2 to 1.5 percent of Si, 0.3 to 1.5 percent of Mn, 1.6 to 6.0 percent of Cr, less than or equal to 3.5 percent of W and Mo, less than or equal to 1.5 percent of Ni and Cu, less than or equal to 1.5 percent of V, less than or equal to 0.15 percent of Re, less than or equal to 0.10 percent of Ba and Mg, less than or equal to 0.05 percent of K and Na, less than or equal to 0.015 percent of S, less than or equal to 0.002 percent of O and the balance of ferrum, and trace impurities which are difficult to measure; and a work layer of a supporting roll comprises the following chemical components in percentage by weight: 0.4 to 1.0 percent of C, 0.3 to 2.0 percent of Si, 0.6 to 2.5 percent of Mn, 1.0 to 4.5 percent of Cr, less than or equal to 1.5 percent of W and Mo, less than or equal to 1.5 percent of Ni and Cu, less than or equal to 1.0 percent of V, less than or equal to 0.15 percent of Re, less than or equal to 0.10 percent of Ba and Mg, less than or equal to 0.05 percent of K and Na, less than or equal to 0.02 percent of S and less than or equal to 0.003 percent of O. Liquid steel is refined repeatedly and metamorphosed complexly in and out of a furnace to improve the purity of the steel and refine metallographic structures and carbide particles; gas protection and liquid steel filtration are performed in the process of steel taping and casting; and the metallurgical fusion of a metal type blank for making the roll sleeve and a roll core is performed during casting by a CPC method to prepare a composite cold roll, so the method has remarkable energy saving and consumption reduction benefits.