The invention discloses a medicament for treating infantile asthma and a preparation method thereof and belongs to the field of Chinese medicine. The medicament is prepared from, by weight, honeyed herba ephedrae, boiled bitter almonds, parched white paeony roots, uncaria stems, parched perilla seeds, plantain seeds, radish seeds and radix scutellariae which are adopted as the raw materials according to a certain proportion. The medicament can be prepared into any common oral dosage form, has the efficacy of ventilating the lung, resolving phlegm and relieving cough and asthma, and can be usedfor treating infantile asthma with the symptoms of exogenous cold and endogenous heat, wherein the specific symptoms include cough, asthma, tinnitus, thick and yellow phlegm, chest distress, rhinorrhea, sneeze, pharyngitis, thirst or fever with aversion to cold, anxiety during sleep at night, yellow urine, dry feces, the red tongue with a thin and white or yellow tongue coating, high strength orhigh frequency of the pulses, and red or deep purple fingerprints. It is clinically verified that the medicament has an obvious treatment effect and is free of toxic or side effect, and the effectiverate reaches 96.67% or above.