Abstract:Juglans mandshurica Maxim. tannins was extracted by ultrasonic method. Tannins content was determined by UV spectrophotometry. The effects of the volume fraction of acetone, ultrasonic temperature, ultrasonic time, and ratio of material to liquid on tannins were evaluated by orthogonal test method in the ultrasonic experiment. The optimal extraction conditions for the tannins in green peel of J.mandshurica were the volume fraction of acetone of 40%, ultrasonic temperature of 40℃, extraction time of 30 min, and solid-liquid ratio of 1∶15. The optimal extraction conditions for the tannins in leaves of J.mandshurica were the volume the fraction of acetone of 50%, ultrasonic temperature of 60℃, extraction time of 40 min, and solid-liquid ratio of 1∶20. The tannins in both green peel and leaves had excellent scavenging capacity for hydroxyl radical, nitrite ions and superoxide anion. The ability of scavenging three kinds of free radicals of the tannins in leaves was stronger than that of the green peel. J.mandshurica tannins had strong antioxidation, and the tannins was with potential pharmaceutical value as a good natural antioxidant.