In this study, single-factor experiments were used to explore the effects of pulse number, material-to-liquid ratio, and field strength on the yield of flavonoids extracted from Exocarpium Citri grandis in aqueous medium with high-voltage pulsed electric field auxiliary extraction technology and the optimum extraction conditions were sorted out by a response surface methodology. The flavonoids were purified by ethyl acetate extraction and AB-8 macroporous resin adsorption method. Meanwhile, the anti-oxidant activity in vitro was studied through ，1-diphenyl-2-trinitrophenylhydrazine (DPPH) method, 2， electric field intensity 7.8 kV/cm, and the material-liquid ratio 1∶70. With this optimal condition, the yield reached up to 30.34 mg/g. The mass fractions of flavonoids purified by macroporous resin adsorption and ethyl acetate extraction were 51.20% and 20.90% respectively showing that the macroporous resin adsorption was superior. Their IC50 in DPPH method were 428.16, 112.43, 256.64 μg/mL, and that in ABTS method were severally 31 797.5， 64 345.74, 68 164.48 mg/(100 g). The FRAP value of macroporous resin adsorption, ethyl acetate extraction, and crude extract of flavonoids decreased sequentially which were consistent with the antioxidant capacity determined by the DPPH method.