Abstract: The antioxidant activity of phenolic extracts from Sphallerocarpus gracilis stem leaves was studied.The antioxidant activity of the extract was evaluated by spectrophotometry on its ability of scavenging 1-diphenyl-2-picrylhydrazy (DPPH·) , hydroxyl radical (·OH) , superoxide anion radical (O2-·) , nitrite, β-carotene bleaching test, and total reducing power. BHT and VC were used as positive control. Results indicated that the polyphenol extracts had a good antioxidant capacity, some indicators even better than the positive control. In addition, polyphenol extracts and purified in a different measurement system in the scavenging ability were quite different at the same concentration (p<0.05) . It could be used as natural antioxidants further developed and utilized.