Highlights • A salt-eluted polysaccharide (SPS-2) was isolated and purified from hawthorn. • Monosaccharide composition and FT-IR analysis indicated that SPS-2 may be pectin. • The antiglycation activity of SPS-2 was significantly higher than WPS in vitro. • MM-POS had the highest antiglycation activity among SPS-2 degradation products. • Ultrasound increased neutral sugar content and decreased antiglycation activity of MM-POS. Abstract The crude polysaccharide was extracted from hawthorn (Crataegus pinnatifida Bunge. Var. major) and a salt-eluted polysaccharide (SPS-2) was fractionated by DEAE cellulose-52 chromatography. Monosaccharide composition and Fourier-transform infrared (FT-IR) analysis indicated that the SPS-2 contained 72.3% galacturonic acid and may be pectin. The results of antiglycation activity in vitro showed that the medium molecular weight pectin oligosaccharide (MM-POS) had the highest antiglycation activity among SPS-2 degradation products. Moreover, the MM-POS obtained by enzymatic degradation had stronger antiglycation activity than that by ultrasonic assisted enzymatic degradation. Composition analysis of MM-POS obtained from ultrasound-assisted enzymatic degradation showed that polygalacturonans content decreased from 85.1% to 61.9% but the arabinan and rhamnogalacturonans increased from 10.6% to 22.7% and from 3.5% to 13.2%, respectively, compared to the MM-POS obtained from enzymatic degradation. This study will provide a theoretical basis for the application of POSs in the food field, especially the exploitation of antiglycation agents. [ABSTRACT FROM AUTHOR]