The invention belongs to the technical field of traditional Chinese medicines, and particularly relates to a formula and a preparation method of a traditional Chinese medicine for treating chilblain. The traditional Chinese medicine is prepared from the following components in parts by weight: 10-35 parts of mongolian ammopiptanthus leaf, 10-30 parts of dried ginger, 2-8 parts of flos carthami, 5-18 parts of radix angelicae pubescentis, 10-20 parts of pepper, 15-25 parts of haws, 15-25 parts of farfugium japonicum, 3-8 parts of asarum, 10-20 parts of cinnamon, 3-8 parts of dragon blood, 5-15 parts of cortex phellodendri, 10-20 parts of licorice roots, 2-10 parts of Chinese dates, 3-8 parts of clematis chinensis and 3-8 parts of mirabilite. The preparation method comprises the following steps: adding mongolian ammopiptanthus leaf, asarum, dragon blood, radix clematidis and chloranthus japonicus into water, and decocting for the first time; adding dried ginger, flos carthami, radix angelicae pubescentis, pepper, haws, farfugium japonicum, cinnamon, cortex phellodendri, licorice roots, Chinese dates, clematis chinensis, masson pine, sambucus chinensis, solidago decurrens, akebia trifoliata, garlic, lindera glauca, stephania japonica, sargentodoxa cuneata and radix achyranthis bidentatae, and decocting for the second time; adding mirabilite into the materials in the step 2, decocting for the third time, and filtering residues to obtain decoction. The composition is prepared from natural traditional Chinese medicinal raw materials, and is simple and convenient to prepare, wide in medicinal material source and low in cost.