The invention discloses a method for extracting gamma-polydiaminobutyric acid and polylysine from fermentation liquor, which comprises the following steps of: pretreating the fermentation liquor, adsorbing and desorbing by using resin, decolorizing, concentrating, and drying; and performing drying treatment respectively to obtain the finished products of the polylysine and the polydiaminobutyric acid respectively. Raw materials and instruments are readily available and low in cost; an extraction and purification process is simple and feasible; the finished products have high yield and purity; and the method is environment-friendly, and suitable for industrial mass production.