Abstract: In order to get the optimal solution to extract polyphenols from kernel and kernel seedcase, the ultrasonic apparatus was applied to treat sample, the independent variable were the ratio of raw material to water, ultrasonic temperature, ultrasonic power and time, the responses was content of kernel and kernel seedcase polyphenols.The orthogonal test analysis showed that the optimal ultrasonic conditions of kernel polyphenol determined were as: ratio of raw material to water 1 ∶ 10, ultrasonic temperature 50 ℃, ultrasonic power 400 W and ultrasonic time 60 min, and The optimal ultrasonic conditions of kernel seedcase polyphenol was ratio of raw material to water 1 ∶ 10, ultrasonic temperature 60 ℃, ultrasonic power 400 W and ultrasonic time 60 min. It also analyzed the antioxidant ability differences of kernel and kernel seedcase polyphenols using reducing power assay, OH, DPPH, ABTS radical-scavenging rate in order to provide a reference for the development of kernel polyphenol functional ingredients.The results showed that the antioxidant capacity of kernel polyphenol was positively related to polyphenol content.The sweet kernel polyphenol was higher than bitter kernel in reducing power assay and OH, ABTS radicalscavenging rate, and basically the same in DPPH radical-scavenging rate, 25.4% and 23.7% in turn at 0.024 mg/m L of sweet and bitter kernel polyphenol. The antioxidant capacity of kernel seeacase polyphenol was not obvious, basically consistent in reducing power assay and DPPH, ABTS radical-scavenging rate in sweet and bitter kernel polyphenol. However, the sweet kernel seedcase polyphenol was two times than bitter kernel at 0.24 mg/m L in OH radical-scavenging rate. On the whole, the antioxidant capacity of sweet kernel polyphenol was better than the bitter kernel polyphenol, which had higher potential value.