The invention discloses a method for extracting radix codonopsis extract. The method comprises the steps that one part of radix codonopsis is placed in a drying box, radix codonopsis is dried till the water content of radix codonopsis is smaller than or equal to 5%, and grinding is carried out; electronic beams with the strength being 10 kGy are used for irradiation; radix codonopsis powder is added into 70% ethyl alcohol with the pH value being 5, water bath ultrasonic treatment is carried out for 5 min, stirring is carried out for 1 h, suction filtration is carried out, first filtrate and first filter residues are obtained, the first filtrate is subjected to rotary evaporation, and a mixture A is obtained; the first filter residues are placed in eight parts of organic solvent, water ultrasonic treatment is carried out for 5 min, stirring is carried out for 30 min, suction filtration is carried out, second filtrate is obtained and subjected to rotary evaporation, and a mixture B is obtained; second filter residues are added into 50 parts of deionized water, digesting is carried out for 10 min, the mixture is cooled to 30 DEG C, suction filtration is carried out, third filtrate is obtained, reduced pressure distillation is carried out, and a mixture C is obtained; the mixture A, the mixture B and the mixture C are placed in 15 parts of absolute ethyl alcohol, the mixture is placed in a water bath at the temperature of 50 DEG C, stirring is carried out for 20 min, the mixture is placed in a refrigerator, the temperature is below 5 DEG C, standing is carried out for 10 h, suction filtration is carried out, liquid is filtered out, and the radix codonopsis extract is obtained. According to the method, nutrient substances in radix codonopsis are efficiently and safely extracted.