The invention discloses a medicine for treating parasitic diseases of pigs and a preparation method thereof. The medicine comprises the following raw medicinal materials: Mexican tea herb, cyrtomium rhizome, dark plum fruit, pomegranate root, bigfruit Elm product, bark of David christmashush, areca seed, pumpkin seed, herb of Wilson passionflower, amur corktree bark, stem and leaf of bird rape, seedling in cushaw, pepperweed seed, leaf of betel pepper, honeysuckle stem, heterophylly falsestarwort root, rangooncreeper fruit, radix astragali, coptis root, malt sugar, honey, bistort rhizome, common burreed rhizome, zedoray rhizome, aloe, dried tangerine peel, parslane herb and rhizoma dioscoreae. The medicine has the beneficial effects that the medicine has the functions of killing and expelling parasites, has good curative effects mainly on parasitic diseases of pigs, has strong pertinence and direct expelling property, is cheap, is nontoxic and harmless, does not have residues, is safe and convenient, has comprehensive functions and can achieve the effects of improving the physiques of pigs, boosting the immunities of pigs, increasing the survival rate and increasing the market benefits.