Abstract: A preparation method of a plant-mixed warm regenerated asphalt mixture, comprises the following steps: preparing a RAP material, a new aggregate, a mineral powder, a new asphalt and a regenerant with a total mass percentage of 100%; heating and stirring the RAP material, adding the regenerant, and continuing to heat and stir; placing the product in a development bin for development, wherein a development temperature is 40° C. to 150° C., and a development time is 0.5 h to 6 h; mixing, heating and stirring a product with the new aggregate; and after mixing and heating the product with the new asphalt, adding the mineral powder, and stirring to mold. Addition of the regenerated asphalt mixture in the development process improves the regeneration effect of the old asphalt, and pavement performances of the formed regenerated asphalt mixture can fully reach that of a hot-mixed asphalt mixture produced entirely with new materials.