Six kinds of crude polysaccharides were precipitated with 80%, 70%, 60%, 50%, 40% and 30% ethyl alcohol respectively from Ribes nigrum fruit. Then the DPPH?, OH?and O2-?scavenging activities were investigated after purified by macroporous resin D4006. The results showed that six kinds of polysaccharides had certain scavenging activities and the polysaccharides precipitated with 80% ethanol (BCP-1) had stronger free radical elimination capacity. Homogeneous component (BCP-1-Ⅱ) was prepared after further purification from BCP-1 by Sephadex G-100. The compositions of the main fraction BCP-1-Ⅱ were identified and quantified by GC and HPLC. Results indicated that BCP-1-Ⅱhad an average molecular weight of 51880 u and contained arabinose, mannose, glucose and galactose with the molar ratio of 9.08:1.00:15.77:0.41. Characteristic absorption of polysaccharide was shown in IR spectrum and the monomer of backbone of BCP-1-Ⅱ might be α-pyranose.