The invention discloses medicine for treating infant damp-heat type diarrhea and a preparation method thereof. The medicine comprises the following raw medicinal materials: eupatorium fortunei, astilbe chinensis, radix salviae miltiorrhizae, adenosma indianum, herba lycopodii, Chinese sage herb, folium viticis negundo, folium et cacumen murrayae, seeds of brassica campestris, lysimachia sikokiana, herba scutellariae barbatae, semen aesculi, latouchea fokiensis, persicaria hydropiper, radix pseudostellariae, radix glycyrrhizae, bulbus allii macrostemonis, aster ageratoides, herba lycopi, common origanum herb, radix rubiae, rhizoma atractylodis macrocephalae, vitis flexuosa juice, mosla Chinensis maxim, herba asari, pittosporumlike nothapodytes, myrrh, radix angelicae, radix astragali, elsholtzia rugulosa, semen raphani, achyranthes aspera, sweet basil herb, greater celandine herb and chinaroot greenbier rhizome. The medicine has the benefits of having the efficacies of relieving exterior syndrome, resolving dampness, regulating qi, regulating the middle warmer, and activating blood circulation to remove blood stasis, having the effects of protecting gastrointestinal mucous membrane, enhancing resistance and relieving pain, and having the advantages of taking effect quickly, and being high in efficiency, accurate in curative effect, short in treatment course, free of toxic and side effects, low in price, and the like.