Abstract: After yam flesh were exposed to hot water extraction and then purified by DEAE-52 and SephadexG-75 columns，two pieces of glycoproteins in Chinese yam were obtained，i.e. CYG-1 and CYG-2. The antioxidant activities in vitro of the two glycoproteins were investigated. The results showed that the two glycoproteins had scavenging activities against hydroxyle radical（·OH），hydrogen peroxide （H2O2），superoxide anion radical（）and 1，1-diphenyl-2-picryl-hydrazyl（DPPH）as well as inhibiting capacity of lipidsome peroxidation. There were positive relations between CYGs concentrations and their antioxidant activities. There were some differences on antioxidant activities between CYG-1 and CYG-2. Generally，CYG-2 exhibited better effects than CYG-1.

Key words: Chinese yam, Dioscorea opposite Thumb., glycoprotein, antioxidation activity, in vitro