OBJECTIVE：To compare antioxidant activity of different extraction parts from flower buds of Buddlejae flos in vitro. METHODS：Ethanol crude extract（ET）was extracted from flower buds of B. flos with 60％ ethanol and diffused by water； and petroleum ether，ethyl acetate and n-butanol were used to extract ET to obtain PE，EA，BU and water samples（SH）. Using dibutyl hydroxy toluene（BHT）as positive control，the antioxidant capacity of PE，EA，BU and SH were investigated by using 1， 1-diphenyl-2-picrylhydrazyl（DPPH），2，2′-azino-bis（3-ethyl benzothiazoline-6-sulfonic acid）diammonium salt（ABTS）free radical scavenging method and ironion reduction/oxidation resistance ability （FRAP） method. IC50 and antioxdant equivalent TEAC were calculated. RESULTS：Compared with other samples，ET and EA had stronger antioxidant activity，and IC50 of EA scavenging DPPH and ABTS free radical were 13.75，9.78 μg/ml，and those of ET were 14.93，11.41 μg/ml；scavenging ability of EA to DPPH free radical was stronger than that of BHT（IC50 was 18.71 μg/ml）. TEAC of EA，ET and BHT were 1 657.67，1 586.25 and 1 581.68 μmol/g. CONCLUSIONS：The ethyl acetate extract from flower buds of B. flos has good antioxidant activity.