The invention relates to a traditional Chinese medicine composite for treating nephritis and a preparation method thereof. The composite is prepared from nine traditional Chinese medicines: honeysuckle, divaricate bassia herb, Amaranthaceae, plantain seed, Houttuynia cordata, cogongrass rhizome, fructus rosae laevigatae, lotus seed and stamen nelumbinis. A preparation method of the traditional Chinese medicine composite for treating nephritis comprises the following steps of: selecting the dry raw materials of the nine traditional Chinese medicines, cleaning and sterilizing; weighing in weight ratio; putting in a drying oven and drying; mixing the dried raw materials of the traditional Chinese medicines; crushing into fine powder; adding water until the volume is two times the total amount of the medicines; soaking for 20-60 minutes; carrying out heating reflux for 80-120 minutes; filtering liquid; then adding water; carrying out reflux for 50-80 minutes; and then discarding residues to prepare the decoction or the powder of the traditional Chinese medicine formula for treating the nephritis, wherein the decoction is packaged by a 100ml or 200ml container, and the powder is packaged by 3g per bag. The composite takes the obvious therapeutic action on the nephritis while improving the nutrition state of a nephritis patient.