Abstract: Four different extraction methods of propolis were used in this experiment. The Propolis extracted by the four methods was diluted into 0.8%, 0.4%, 0.2%, 0.1%. The given five kinds of bacterial were Bacillus cereus, Escherichia coli, Staphylococcus aureus, Salmonella sp, Aspergillus sp. The antibacterial activity of propolis against the five given bacterial were investigated. The diameters of inhibiting zones and MIC (minimum inhibitory concentration) were measured in mm. The results showed that the extraction rate of 95% EtOH and ultrasonic wave was highest, the extraction rate is 27.3%; the bacteria could be inhibited by the liquid of propolis in varying degrees, the antibacterial activity liquid of propolis through 95% EtOH and ultrasonic wave was strongest. It was found that the inhibition effects on Escherichia coli was best and that on Aspergillus sp. was worst.

Key words: propolis； ultrasonic wave； inhibitive cycle&rsquo, s diameters； MIC；