Abstract: In this experiment, corn silk polyphenols were taken as the research object. Based on the single factor experiment, response surface methodology was used to optimize the ultrasonic-assisted extraction process of corn silk polyphenols. The effects of ultrasonic frequency, ultrasonic power, ultrasonic temperature and ultrasonic time on the extraction rate of corn silk polyphenols were investigated, and the antibacterial activity of corn silk polyphenols against Escherichia coli and Staphylococcus aureus was also explored. The results showed that under the conditions of ethanol concentration 60%, liquid-solid ratio 30:1, ultrasonic frequency 40 kHz, ultrasonic power 350 W, ultrasonic temperature 56 ℃ and ultrasonic time 45 min, the extraction rate of corn silkpolyphenols were (13.31±0.12) mg/g; The antibacterial activity test showed that corn silk polyphenolswith different concentrations had certain inhibitory effect on Escherichia coli and Staphylococcus aureus, and the minimum inhibitory concentrations were 2.5 mg/mL and 2 mg/mL respectively.