The invention provides medicine for treating chronic constipation and a preparation method thereof. The medicine is prepared from radix scrophulariae, radix ophiopogonis, cimicifugae foetidae, immature bitter orange, prepared aconite roots, frying semen raphani, cistanche, raw rhizoma atractylodis macrocephalae, angelica sinensis, elecampane, agilawood, fructus cannabis, semen boitae, polygonum multiflorum, lindera aggregate, herba houttuyniae, astragali radix, mangnolia officinalis, rhubarb stir-fried with wine, cinnamon, radix polygonati officinalis, pericarpium arecae, honeysuckles, fructus forsythiae, radix clematidis, fructus gleditsiae and other Chinese herbal medicine. The medicine has functions of tonifying qi and nourishing blood, clearing heat and removing dryness, and relaxing bowels, has a remarkable curative effect on treating chronic constipation especially elderly chronic constipation, and is safe in dosage and free of side effects.