Abstract: Using Taraxacum kok-saghyz Rodin (TKS) roots as the raw material, the liquid-solid ratio, ultrasonic power, extraction temperature, and extraction time were selected as experimental factors. On the basis of single factor experiments, the response surface methodology was used to optimize the ultrasonic-assisted extraction process of polyphenols from the TKS roots. The in vitro antioxidant and hypoglycemic activity of the polyphenols extracted from TKS roots were measured. The results showed that the optimal extraction conditions were liquid-solid ratio of 33:1 mL/g, ultrasonic power of 270 W, extraction temperature of 61 ℃, and extraction time of 31 min. Under these conditions, the yield of polyphenols from TKS roots was 1.46%±0.03%. The in vitro activity test showed that the half inhibitory concentrations (IC₅₀) of polyphenol extracts on DPPH and ABTS⁺ radicals were 54.06 and 39.27 µg/mL, respectively, the IC₅₀ values for α-amylase and α-glucosidase were 133.26 and 50.22 µg/mL, respectively. This indicated that the polyphenols from TKS roots had strong antioxidant and hypoglycemic activities in vitro. This study can provide theoretical basis for the comprehensive development and utilization of TKS.