The objective was to study extraction technique and purification technique of Rhizoma Chuanxiong.Orthogonal experiment design and single factor tests were used for optimizing the extraction and purification technol. of Rhizoma Chuanxiong by measuring transition probability.Rhizoma chuanxiong was reflux-extracted with water, and purified with the methods of ethanol deposition, 20% calcium hydroxide-sulfuric acid-ethanol and water deposition.Transference rate of ferulic acid could arrive at 77.01%, and the impurities such as protein, oxalate, tannin and resin were all removed.