The compound solution of plant essential oils were prepared by solvent agent and emulsifying two kinds of diluent carrier， and its quality was evaluated. The antibacterial activity was studied by measuring the minimum inhibitory concentration （MIC） and minimum bactericidal concentration （MBC）. Result showed that anhydrous ethanol as solvent agent can effectively improve the aqueous solubility of essential oils， but its overall antibacterial effect was less than 1，2-propylene glycol. The stable oil-in-water microemulsions could be fabricated using Tween-80 as a surfactant， anhydrous ethanol as a cosurfactant and oregano-thyme compound（1 ∶ 1） as an oil phase via construction of pseudo-ternary phase diagrams， which was a light yellow and transparent liquid. When the ratio of Tween 80 to anhydrous ethanol was equal to 3 ∶ 1， the system has the largest area of microemulsion region （29.55%） and the minimum dilution ratio （9 ∶ 1）. Characterized for its droplet size distribution， polydispersity index （PDI）， viscosity， Zeta potential， the microemulsion formula （10 ∶ 1 ∶ 28） was found to have the lowest droplet size（13.0nm ± 0.6nm）， the lowest PDI （0.231 ± 0.020） and optimal Zeta potential （-22.23mV ± 0.24mV）. Essential oil by emulsion have better resistance to salt， glucose， acid and alkali， as well as good storage stability. However， the antibacterial effect of microemulsion were found to be greatly weaken against the tested microorganisms. The research results provide a theoretical basis for the edible plant essential oils applied to the field of food preservation with its characteristics of high efficiency and safety.