The invention discloses a medicament with an effect of treating chronic eczema and a preparation method thereof. The medicament is prepared from the following raw materials: green tea, sanguisorba officinalis, spina gleditsiae, fructus gleditsiae, tribulus terrestris, periostracum cicada, sophora flowers, fruit of nitraria, radix clematidis, thesium chinensis, lily magnolia, rose flowers, ginseng flowers, bletilla striata and xylitol. The medicament is specially researched and developed for patients with chronic eczema; the chronic eczema is a stubborn pruritus skin disease; the medicament has the effects of removing exterior and interior wind, dispersing the acrid flavor, warming the channels, eliminating the swelling, clearing toxic materials, calming wind, killing worms, removing gastrointestinal damp stasis, eliminating wind, relieving itching and clearing toxic materials, clearing away heat and toxic materials, dispelling wind and heat, whitening the skin, removing gastrointestinal joint heat, removing damp heat source, and treating both symptoms and root causes; unique traditional Chinese medicines are selected to be fused with the green tea to form the medicament; the process is safe and quick; the purpose of easily treating the chronic eczema of the patients in daily life is achieved.