The invention belongs to the field of natural product chemistry, and relates to extraction, separation and purification of natural products, in particular to a technical method for extracting high-purity total alkaloids from dyers woad leaf. The method for preparing indigo and indirubin from dyers woad leaf is mainly characterized by comprising the following steps of: drying, pulverizing and sieving dyers woad leaves; heating and extracting by reflux by an ethanol solution containing sodium hydroxide; recovering ethanol from filtrate; concentrating the filtrate, regulating the pH to be neutral by a hydrochloric acid solution, centrifuging; dissolving the precipitate by the hydrochloric acid solution, and centrifuging to obtain supernatant for later use; performing microfiltration on the supernatant in membrane separation equipment; loading the stock solution after microfiltration on a resin column for absorption, then eluting with water to remove water soluble impurities, discarding the water eluent; eluting with aqueous ethanol, collecting the eluent; and recovering ethanol from the eluent, concentrating and drying to obtain a dark red product. The method has the advantages of low production cost of the products, simple process route, smaller toxicity of the extraction solvent and short extraction cycle, and is suitable for application in industrial production. Based on the advantages, the method can further promote industrialized development of the dyers woad leaf extract as a multifunctional product such as a medicine, a health product and the like.