LBP-I was obtained by isolation and purification from dry fruits of Lycium barbarum L. ( Fructus Lycii) and it was shown to be single substance by ion exchange and gel chromatography. The results showed that LBP-I is a kind of glycoproteins composed of protein and acidic heteropolysaccharide consisting of galacturonic acid and neutral saccharide. The neutral saccharide contained galactose, glucose, rhamnose, arabinose, mannose and xylose in mole ratio of 5. 17∶ 4. 13∶ 3. 15∶ 1. 00∶ 0. 84∶ 0. 48. The contents of neutral saccharide, galacturonic acid and protein are 81. 37% , 3. 69% , 9. 24% , respectively. The molecular weight is more than 20 000. IR analysis showed that main chains composed of α-pyranglycoside linkage.