[Objective] To study the ultrasonic extraction technology of flavonoids from G. biloba leaves. [Method] The flavonoids were first extracted from G. biloba leaves by ultrasonic method in different conditions then identified by UV spectrophotometry. On the basis of single-factor tests, the factors that affected the extraction of flavonoids were optimized. [Result] The optimal parameters for extracting flavonoids from G. biloba leaves were based on the extraction for 90 min at 60 ℃ with 70% ethanol as solvent in the acidic condition (pH=5.0). Moreover, the extraction system oscillated for 3 times of 10 min each time. Under the above conditions, the yield of flavonoids was 0.201 2%. [Conclusion] This study screens out the optimum ultrasonic extraction technology of flavonoids, which could provide theoretical basis for the development and utilization of G. biloba leaves. [Objective] To study the ultrasonic extraction technology of flavonoids from G. biloba leaves. [Method] The flavonoids were first extracted from G. biloba leaves by ultrasonic method in different conditions then identified by UV spectrophotometry. On the basis of single-factor tests , the factors that affected the extraction of flavonoids were optimized. [Result] The optimal parameters for extracting flavonoids from G. biloba leaves were based on the extraction for 90 min at 60 ° C with 70% ethanol as a solvent in the acidic condition (pH = 5.0%.) The study screens out the optimum ultrasonic extraction technology of flavonoids, which could provide theoretical basis for the development and utilization of G. biloba leaves.