Abstract: To study the antibacterial activity of the extracts with different solvent from Fructus berberis. Microwell plate method and double dilution method were used to determine the minimum inhibitory concentration (MIC) of the extracts of Fructus berberis against streptococcus mutans and Escherichia coli. The results showed that the ethanol extrac, water extract, ethyl acetate extract and n-butanol extract could inhibit the formation of biofilm of stretopcoccus mutans. The ethyl acetate extract had certain inhibition on the growth of Escherichia coli. The n-butanol extract, ethyl acetate extract and chloroform extract could inhibit the formation of biofilm of Escherichia coli, especially chloroform extract showed the obviously antibacterial activity. Fructus berberis had obvious antibacterial activity composition and were worth further studying.