The invention relates to a traditional Chinese medicine veterinary drug for treating postpartum retention of fetal membranes of cows and a preparation method of the traditional Chinese medicine veterinary drug. The traditional Chinese medicine veterinary drug is prepared from the following ingredients by weight: 10-20 parts of motherwort, 5-20 parts of dandelion, 5-15 parts of angelica sinensis, 6-9 parts of herba epimedii, 5-9 parts of ligusticum wallichii, 5-7 parts of bighead atractylodes rhizome, 4-8 parts of codonopsis pilosula, 4-8 parts of astragalus membranaceus, 4-8 parts of hawthorn, 4-7 parts of semen cuscutae, 3-8 parts of bunge corydalis herb, 3-5 parts of rhizoma cyperi, 2-5 parts of immature bitter orange, 2-4 parts of peach kernel, 2-4 parts of eucommia ulmoides, 2-3 parts of red flowers, 1-3 parts of lonicera japonica and 1-2 parts of honey-fried licorice root. One or more of pericarpium citri reticulatae, pinellia ternate, trogopterus dung, mangnolia officinalis, rehmannia glutinosa, ophiopogon japonicus, fructus forsythiae and rhizoma zingiberis can be added. The traditional Chinese medicine veterinary drug belongs to a nature pure traditional Chinese medicine preparation, the method for curing postpartum retention of fetal membranes of cows is simple and is easy to operate, the effect is significant, no side effect exists, and no medicine residual exists in milk. The absorption is good through oral administration, and the preparation method has a simple process, is suitable for industrial production, and has the characteristic of simplicity, convenience and fastness in use. Compared with other preparations, the traditional Chinese medicine veterinary drug is more suitable for treatment of postpartum retention of fetal membranes of cows in large-scale livestock farms.