The invention relates to a Chinese medicine decoction for treating a knee joint pain associated with hydrops. The Chinese medicine decoction is prepared from the following crude medicinal materials by weight: 60g of astragalus membranaceus, 20g of angelica sinensis, 12g of peach kernel, 12g of flowers carthami, 30g of caulis spatholobi, 12g of dried body of ground beetle, 15g of dipsacus root, 10g of eucommia ulmoides, 20g of madder, 12g of angelica grosseserrata, 20g of rhizoma atractylodis, 20g of pawpaw, 60g of honeysuckle stem, 30g of geranium wilfordii, 20g of parasitism, 12g of medicinal cyathula root, 60g of seed of job's tears, and 12g of golden cypress. The Chinese medicine decoction has the functions of relieving the knee joint pain, removing the hydrops and the like, has significant curative effects on treatment of gonitis, knee osteoarthritis and the like, and has no toxic and side effects; the effective rate can be up to 93.3%.