The invention discloses a casting method for improving a structure and a performance of a ductile cast iron material. The casting method comprises the steps of (A) designing a metal mold: designing and manufacturing a random metal mold according to a shape structure of a casting piece, wherein the heat conductivity and the heat capacity of a metal mold material and a casting piece material are approximate, and the ratio of a metal mold wall thickness to a casting piece wall thickness is 0.8 to 1.2:1; (B) preprocessing the metal mold and a sand core: preheating the metal mold, then uniformly painting a water-based paint on an inner wall, meanwhile, uniformly painting an alcohol-based paint on a precast sand core surface, closing a mould after painting the paints, and feeding hot air for processing; and (C) casting the casting piece. The invention further discloses a casting piece casted through the method. According to the casting method for improving the structure and the performance of the ductile cast iron material, and the casting piece casted through the casting method provided by the invention, the metal mold with high heat conductivity and heat capacity is adopted to be casted, and a solidification process of the casting piece is controlled through adjusting the metal mold wall thickness, so that the cooling speeds of different thickness parts of the casting piece can beeffectively adjusted, the overall cooling speed of the casting piece is increased, the casting piece is quickly cooled to form a fine grain, and the structure and the performance of the casting pieceare improved.