Antibacterial activities of the bamboo(Pseudosasa japonin Makino) leaves extract on lactic acid bacteria related to Dongchimi fermentation were investigated. The bamboo leaves were extracted with 70% ethanol, fractionated it with 4 solvents which have a different polarity. Total viable count was very similar to those obtained by lactic acid bacteria during fermentation of Dongchimi. Its maximum counts were (equation omitted) 10$^{7}$ CFU/m1 at 8 days of fermention. Lactic acid bacteria isolated during Dongchimi fermentation were identified as Leuconostoc species(BK-2, BK-07, BK-22), Lactobaillus species (BK-05, BK-08) and Streptococcus species(BK-15) 70% ethanol extract of the bamboo leaves showed antibacterial activity against strain BK-02, BK-07, BK-lS and BK-22. Especially, strain BK-22 was more effective to the extracted substance. Among the each fractions, 70% ethanol and diethyl ether had the strongest antibacterial activity against strain BK-22 and BK-07, respectively. The two fractions also showed similar activities against all of the test strains.