The invention relates to a traditional Chinese medicine for treating conjunctivitis and a preparation method thereof. The formula of the traditional Chinese medicine comprises the following ingredients: 6-12 g of poria peel, 7-15 g of artemisia capillaris, 9-14 g of radix stephaniae tetrandrae, 25-35 g of coix seed, 8-13 g of radix saposhnikoviae, 8-16 g of dahurian angelica root, 26-35 g of fructus kochiae, 8-15 g of honeysuckle, 6-14 g of fructus forsythiae, 26-32 g of heartleaf houttuymia herb, 4-8 g of stir-baked fructus gardeniae, 11-17 g of zaocys and 16-24 g of herba erodii. All the thirteen ingredients are immersed in water, and are boiled by vigorous fire and then decocted by mild fire for 20-30 minutes; and the oral administration of the medicine is one dose per day. The traditional Chinese medicine has the main efficacy of expelling wind and removing dampness, clearing away heat and toxic material and relieving itching, and is mainly used for treating spring catarrhal conjunctivitis.