The invention belongs to the technical field of material machining, and in particular, relates to a preparation method of a high-strength/toughness classification structured metal base composite material. The preparation method comprises the following specific steps: (1) flaky metal powder is obtained by basal body alloy powder through high-energy ball milling; (2) reinforcing bodies and the obtained flaky metal powder are mechanically stirred and ultrasonically dispersed and mixed in dispersion liquid for filtration and drying to obtain composite powder I; (3) the low-energy ball milling is performed on the composite powder I and spherical metal powder to obtain composite powder II; and (4) the composite powder II is formed through cold pressing under pressure for part remelting and thixotropic formation to obtain classification structured metal base composite material mixed powder pressing blocks. The preparation method is simple in principle, simple in operation, safe and reliable,realizes industrial production, meanwhile, improves the working efficiency, saves the materials, guarantees the quality, and achieves safety, reliability and higher application and popularization value.