Abstract: In this study，propolis ethanol extract was used as raw material while olive oil as food grade oil phase，Tween 80 as surfactant，and alcohol as cosurfactant. The propolis oil-in-water nano-emulsion was prepared on the basis of determining the best ratio of the above materials. The mean particle size and distribution of emulsions prepared with different homogenization pressure（0，40，80MPa）were analyzed. As shown in the results，the effects of homogenization pressure on particle size and polydispersity index were significant. The emulsion processed under 80 MPa contained （143.2±1.4） nm of average diameter，uniform size distribution and good stability.

Key words: high-pressure homogenization, propolis, nano-emulsion