The invention discloses a method for extracting total flavonoids in grape seeds in a double-aqueous phase 
system, belonging to the field of separation and 
extraction methods of 
natural product active ingredients. The method comprises the following steps of: firstly preparing 
grape seed rough extract from grape seeds with 
ethanol; then adding absolute ethyl 
alcohol, 
ammonia sulfate, inorganic salt and water in the 
grape seed rough extract to form the double-aqueous phase 
system, mixing uniformly, standing for 5-30 minutes at 
room temperature for 
delamination to obtain an upper phase and a lower phase, concentrating the upper phase through 
pressure reduction and 
drying so as to obtain total flavonoids of 
grape seed. In the double-aqueous phase 
system, the 
mass percents of grape seed rough extract, absolute ethyl 
alcohol, 
ammonia sulfate and inorganic salt are respectively 5% to 30%, 10% to 30%, 16% to 30%, and 0 to 5%, the balance is supplemented to be 100% with water, and the pH of the double-aqueous phase system is 3.0 to 11.0. Flavonoids are extracted by utilizing double aqueous phases in the method; the method is simple, the operation is convenient, the production cost is low and the treating capacity is large, small 
test data can be directly amplified, and the yield of flavonoids in the grape seeds reaches up to 98.2%; and the method can be operated continuously, and is suitable for industrialized production of flavonoids in the grape seeds.