The invention discloses a seedling-cultivating nutritional medium for planting motherwort and a preparation method of the seedling-cultivating nutritional medium. The seedling-cultivating nutritional medium comprises the following raw materials in parts by weight: 400-500 parts of dried dung, 100-200 parts of dried cow dung, 30-50 parts of dried duck dung, 30-50 parts of peanut stem leaf powder, 30-50 parts of loofah stem leaf powder, 10-20 parts of corn cake powder, 10-20 parts of pumpkin stem leaf powder, 5-10 parts of auxin, 5-10 parts of epoxy resin and 5-10 parts of Chinese herb residue, wherein the Chinese herb residue is prepared from motherwort residue, lily residue and dried orange peel residue according to a mass ratio of 3:1:1; the preparation method of the seedling-cultivating nutritional medium comprises the following specific steps: 1, preparing the raw materials; 2, fermenting; 3, mixing; 4, granulating; 5, drying. The seedling-cultivating nutritional medium prepared by the preparation method provided by the invention is purely natural, pollution-free and rich in a variety of nutrients; after application of the seedling-cultivating nutritional medium, the cultivated motherwort can grow fast, has fat and thick leaves and prosperous roots, and has good disease resistance and strong pest and disease preventing performance.