Abstract: Ultrasonic-assisted extraction was adopted to extract main phenolicglycosides and aglycones from Acanthopanax senti-cosus(Rupr.et Maxim.)Harms, including the active ingredients such as syringin, eleutheroside E and isofraxidin. According to Box-Behnken central composite experiment design, the extracting process was designed with three factors at three levels. The three factors are volume fraction of ethanol, extraction time and ultrasonic power. The yield and purity of three target products were selected as responses respectively to optimize the extracting process. Response surface analysis (RSA) was applied to determine the effect of central composite experiment design. The optimum conditions of RSA were as follows:volume fraction of ethanol 59.66%, ratio of solid to liquid 1:6(g:mL), ultrasonic time 44.9min, ultrasonic power 150W. Under the optimum conditions the content of main phenolicglycoside and aglycone was 2.923%, of which the purity of syringin was 1.3%, isofraxidin was 0.093%, eleutheroside E was 1.53%, extract yield was 6.77%.