The invention discloses a medicine composite preventing a cow fetal membrane from retaining and a preparation method thereof, and belongs to the field of veterinary medicine. The medicine composite is composed of chaff flower roots, cluster mallow fruits, motherwort herbs, cinnamon, astragali radix, plantain seeds, sesame oil, safflowers, caulis spatholobi, fringed pink, akebia stems, Chinese angelica, codonopsis pilosula, licorice roots, semen persicae, rhizoma chuanxiong, red halloysite and calcium lactate. According to the preparation method, the medicinal materials are cleaned, weighed and smashed into coarse powder, water which is 1-4 times the medicinal materials is added for extraction, concentration is performed, extract is obtained after drying, and the red halloysite and the calcium lactate are evenly stirred. The medicine composite improves the contractility of the cow uterus, promotes discharging of the fetal membrane, shortens the time for excreting the lochia, and improves propagation performance.