The invention relates to a formula and a production method for preparing brown wheat straw dye. The formula is characterized by adopting dry hibiscus mutabilis, isatis tinctoria, alumen, areca-nut, an iron-ion compound solution and mineral water as main raw materials. The production method comprises the following main steps of sorting, cutting, drying, soaking, boiling, mixing, precipitating, dying and forming a finished product. The invention relates to the formula and the production method for preparing the brown wheat straw dye which is pure natural, pollution-free, environment-friendly and free from toxic and side effects on the human body and prepared by from the pure natural plants.