Optimization ultrasonic-assisted extraction of total flavonoid from leaves of phyllanthus emblica was investigated and its antioxidant capacity was determined. Through single factor experiment and orthogonal experiment, the optimization of ultrasonic-assisted extraction of total flavonoids was determined as follows, including the ratio of material to liquid 1:25 (g/mL), ethanol concentration 60%, ultrasonic power 70 W, and extraction at 60 ℃ for 20 min. Under the control of these conditions, the extraction rate of the total flavonoids from leaves of P. emblica was as high as 14.57%. Moreover, the total flavonoids from leaves of P. emblica were found good scavenging effect. With the use of 0.5 mg/mL total flavonoid, the clearance rate of ·OH was found to be 82.72%, and that of NaNO₂ was 66.14%. When 0.08 mg/mL total flavonoid was used, the clearance rate of DPPH· was determined to be 97.40%.