In order to study the optimal extraction process of total flavonoids from Sophorae Flos Immaturus (TFSFI) and its antioxidant activity,the yield of TFSFI was used as evaluation index,the extraction process of TFSFI was optimized by combining single-factor experiments and response surface method,fourier transform infrared spectroscopy and high-performance liquid chromatography were utilized to analyze the interactions during extraction and the main components of TFSFI,the scavenging ability of DPPH and ABTS radicals as well as the ferric iron reduction ability were determined.The results showed that the optimal extraction process for TFSFI using deep eutectic solvents (DES) composed of choline chloride and urea is as follows:molar ratio of urea to choline chloride is 4.1∶1,water content of DES is 27%,ultrasonic temperature is 60 ℃,ultrasonic time is 20 min,ultrasonic power is 240 W,and the yield of TFSFI reaches 25.78%.During the extraction of TFSFI by DES,numerous hydrogen bonds were formed with flavonoids to enhance the extraction efficiency.Furthermore,TFSFI contain components such as rutin,nicotiflorin,narcissoside,quercetin,kaempferol and isorhamnetin,among which the main component is rutin.The IC₅₀ values for scavenging DPPH and ABTS free radicals were 0.32 and 0.23 mg/mL,respectively.When the concentration was 0.19 mg/mL,the FRAP absorbance was 1.05,indicating strong antioxidant capacity.The study provides scientific basis for the effective utilization and further development of Sophorae Flos Immaturus.