Abstract: In order to study the antibacterial activity of turmeric oil,the inhibition zone experiment on Bacillus subtilis,Bacillus cereus,Sarcine luted and Salmonella were used to determine the minimum inhibitory concentration(MIC). The mechanism of antibacterial activity was also studied by measuring the growth curve,conductivity,content leakage and cell morphology of four tested bacterias. The results showed that turmeric oil had antibacterial effect on four kinds of test bacterias,and strongest on Salmonella(The inhibition zone was 15 mm,the MIC value was 0.4 μL/mL),followed by Bacillus subtilis,Bacillus cereus and Sarcine luted. Scanning electron microscope(SEM)showed that turmeric oil damaged the cell morphology and affected the permeability of cell membrane,which resulted the leakage of small molecules. Turmeric oil significantly inhibited the growth of the four tested bacteria in a dose-dependent manner. The four tested bacteria treated with 1 MIC turmeric oil showed that the cell membrane structure was destroyed by the contents of the damaged material, and the conductivity increased significantly. At the same time, the content of protein and reducing sugar in the medium also increased significantly, and the value of OD₂₆₀(nucleic acid) was also obvious. In summary,the antibacterial mechanism of turmeric oil was inferred that it could destroy bacterial cell structure,which would content leakage and lead to cell apoptosis.