The invention relates to a medicament for treating chronic prostatitis. The medicament is prepared from the following raw medicinal materials in parts by weight: 10 parts of lespedeza bicolor, 10 parts of artemisia eriopoda, 15 parts of glabrous tanoak bark, 15 parts of cudrania tricuspidata bur, 6 parts of mongolian oak bark, 30 parts of lindley eupatorium herb, 6 parts of epilobium hirsutum, 9 parts of sealwort, 15 parts of lysimachia hemsleyana, 9 parts of teasel root, 5 parts of calamus, 9 parts of thlaspi arvense, 6 parts of beesia calthifolia, 9 parts of endive, 9 parts of ginseng fruit, 9 parts of ovateleaf holly bark, 9 parts of bauhinia championii, 9 parts of muskmelon seed, 9 parts of common calanthe herb, 9 parts of folium artemisiae argyi, 3 parts of tomentulose corydalis dried herb, 5 parts of flos farfarae, 9 parts of pyrola, 5 parts of lithospermum, 3 parts of dracontomelon duperreanum, 9 parts of black bean, 9 parts of peristrophe, 6 parts of epimedium, 9 parts of rad pouzolzia root and leaf, 5 parts of mulberry leaf, 6 parts of semen sojae praeparatum, 3 parts of globeamaranth flower, 3 parts of inula flower, 3 parts of suchow mosla herb, 6 parts of caltrop and 9 parts of caragana leucophloea pojark. The medicament for treating chronic prostatitis is reasonable in formula, has the characteristics of exact curative effect, no toxic or side effect and low price, and is safe and convenient.