The invention discloses a medicament composition for treating prostatitis and prostatomegaly and a preparation method thereof. The medicament is mainly prepared by the following raw material medicaments: turtle shell, tortoise shell, Indian iphigenia bulb, ground beeltle, sanguisuga, centipede, pangolin scales, raidx astragali, ginseng, rhizoma corydalis, hiraute shiny bugleweed herb, sanchi, peach seed, common macrocarpium fruit, amber, green tangerine peel, rice bean, fennel fruit, sappan wood, pinellia tuber, south dodder seed, rehmannia glutinosa, thunberg fritillary bulb, wax gourd seed,grassleaf sweelflag rhizome, szechwan chinaberry fruit, common yam rhizome, zedoary, sargentgloryvine stem, white mustard seed, Chinese eaglewood, medicinal cyathula root, szechuan lovage rhizome anddragon's blood. The medicament can be prepared into any preparations suitable to be taken orally or externally in clinic according to the traditional Chinese medicament conventional preparation method. Clinical trial results show that the medicament composition has obvious effects on the prostatitis and the prostatomegaly, and toxic and side effects are not seen in clinical observation.