Abstract: Disclosed is a method for purifying pea albumin PAla by using a negatively charged polysaccharide, which belongs to the field of protein extraction technology. According to the invention, with a natural edible negatively charged polysaccharide as a recycling material, based on the technical principle that the negatively charged polysaccharide preferentially binds to non-target proteins to precipitate and undergoes phase separation relative to the target protein, the separation and purification of pea albumin PAla are realized to prepare pure PAla. From the perspective of resource recycling, the invention can realize high value-added utilization of byproducts of pea protein isolate processing and prepare high-purity high-sulfur active protein components therefrom, thereby providing technical support for subsequent research.