The invention discloses a drug for treating a chronic pelvic inflammatory disease and a preparation method of the drug. The drug is prepared mainly by the following materials in a certain proportion by weight: fructus forsythiae, radix salviae miltiorrhizae, tree peony bark, caulis spatholobi, common fennel, pubescent angelica root, cassia twig, carthamus tinctorius, eucommia bark, purslane and the like. The drug has functions of dispersing cold, relieving pain, removing blood stasis, restoring menstrual flow, warming channels and clearing collaterals; and when the drug is used for treating the chronic pelvic inflammatory disease, the effectiveness is instant, the course of treatment is short, and the cure rate is high without recurrence.