Abstract: OBJECTIVE To optimize the extraction technology of polysaccharides extract from Prunus cerasifera by Box-Behnken designing, and to investigate its antioxidant activity. METHODS The effects of extraction time, extraction temperature and liquid-to-material ratio on the yield of polysaccharide extract were established using a 3-factor, 3-lever Box-Behnken design and the structure of polysaccharides was analyzed by IR. RESULTS The optimal extraction condition was obtained as extraction time 61 min, extraction temperature 70℃, liquid-to-material ratio 1:30, ultrasonic time 61 min. Under such condition, the yield of polysaccharides from Prunus cerasifera was 7.20%, and content was 1.41%. Infrared spectroscopy analysis, extracts were glycolic acid and α-D-pyranose. In a certain concentration range, the polysaccharides of Prunus cerasifera had DPPH free radical and hydroxyl radical scavenging ability, showed certain antioxidant activity. CONCLUSION Ultrasonic extraction is simple and easy, and there are abundant polysaccharides in the flesh of Prunus cerasifera plum. The extracted crude polysaccharides from Prunus cerasifera plum have good antioxidant activity.