The invention discloses a medicament for treating refractory insomnia and a preparation method of the medicament. The medicament comprises the following active ingredients in parts by weight: 10-30 parts of astragalus mongholicus, 5-15 parts of Chinese angelica, 5-15 parts of dried rehamnnia roots, 5-15 parts of prepared rehmannia roots, 2-15 parts of golden threads, 5-15 parts of skullcap, 15-25 parts of crude dragon bones, 15-25 parts of raw oyster shells and 2-15 parts of poria with hostwood. The method for preparing the medicament comprises the following steps of: weighing each active ingredient for later use; adding water into the active ingredients to decoct for twice; filtering after each decoction to obtain a filtering liquid; combining the filtering liquids obtained for twice; and concentrating at reduced pressure to obtain extract with crude drug of 5g/ml so as to obtain the medicament for treating the cold. The medicament has the advantages that the formula is scientific, and the curative effect of the medicament is obvious, and the problem that the insomnia is easy to be addicted can be effectively solved.