The embodiment of the invention discloses a preparation method of a multilayer-color composite material for dental department. The preparation method comprises the following steps: preparing N types of monochromatic composite material precursor powder differing in color, and dry-pressing and pre-forming the prepared precursor powder, so that a preformed green body is obtained; and then warming up and heating the preformed green body, so that the multilayer-color composite material is obtained. The multilayer-color composite material for dental department prepared by the method disclosed by the invention has a gradient multilayer color system, so that the aesthetic effect of a dental repair prepared from the composite material is effectively improved; and the composite material can simulate the characteristic of natural tooth that color gradually varies from tooth neck to biting end, so that a higher similarity to the natural tooth is achieved.