The invention provides a pharmaceutical composition used for treating swine dysentery and a preparation method of the pharmaceutical composition. The pharmaceutical composition comprises the following raw herbal materials: smoked plum, anchurian Wildginger herb, rhizoma zingiberis, Angelica sinensis, pricklyash peel, humifuse euphorbia herb, red halloysite, poppy shell, bark of Chinese corktree, coptis chinensis, scutellaria baicalensis, codonopsis pilosula, potentilla discolor, bighead atractylodes rhizome, licorice root, white paeony root, Tacca chantrieri, nutmeg, elecampane, myrobalan, purslane, all-grass of Adder's-tongue and herb of Wideword Parnassia. The pharmaceutical composition has the effects of removing heat to cool blood, regulating qi, promoting blood circulation and stopping dysentery, is super in quality and competitive in price, safe, efficient, easy and simple to operate, low in toxicity, none in drug residue and parasite scruple, and has prodigious help for ponderal growth.