The invention provides an extracting method of 2'-hydroxy-4'-methoxyacetopheone.The method comprises the steps that a water steam distillation and alkali-dissolution and acid-precipitation combined method is adopted to extract 2'-hydroxy-4'-methoxyacetopheone, moutan bark and whole plants of paniculate swallowwort or paniculate swallowwort roots serve as the raw materials, the raw materials are smashed and subjected to water extraction for 10 h-23 h, water steam distillation is conducted, and distillation is stopped when the mass of distillate is 2.5-3 times that of the raw materials; the distillate is cooled and filtered, a product A is obtained, the pH of the raw material and residual liquid in a flask after water steam distillation is conducted is adjusted to be 12-14, and alkali dissolution is conducted; the pH of the solution is adjusted to be 5-7 after alkali dissolution is conducted, acid precipitation is conducted, cooling and filtering are conducted, and a product B is obtained.The method can efficiently extract 2'-hydroxy-4'-methoxyacetopheone, the extraction rate reaches up to 95.3%, and the purity of obtained 2'-hydroxy-4'-methoxyacetopheone reaches up to 98.8%; according to the method, no organic solvent is adopted, environmental pollution is avoided, and environmental friendliness is better achieved.