The purpose of this study was to determine the optimum technological parameters of ultrasonic assisted extraction of pectin from Hawthorn peel residue and study the antioxidant activity of the extracted pectin. Taking the solid-liquid ratio, extraction temperature, ultrasonic power and ultrasonic time as the research factors, on the premise of single factor experiment, the response surface experimental design method was used to establish the corresponding mathematical model and carry out data analysis. The effects of four factors on the yield of pectin in Hawthorn peel residue were as follows: solid-liquid ratio > ultrasonic power > ultrasonic time > extraction temperature. The optimum technological parameters of ultrasonic assisted extraction of pectin from Hawthorn peel residue were as follows: the ratio of solid to liquid 1∶15, the extraction temperature 74 ℃, the ultrasonic power 425 W, and the ultrasonic time 55 min. Under this condition, the optimal extraction rate of pectin from hawthorn peel residue was 6.154±0.041%. In the antioxidant test of pectin ultrasonic-assisted extraction process in hawthorn peel residue, it was found that the extracted pectin had better scavenging ability on hydroxyl radicals and superoxide anion radicals. The ultrasonic assisted extraction process of pectin from hawthorn peel residue optimized by response surface methodology was feasible, and the extracted pectin from hawthorn peel residue had certain antioxidant activity.