The in vitro antioxidant activity of the ethanolic extracts of propolis by high hydrostatic pressure extraction (HHPE) was investigated in relationship to its total polyphenol and flavonoid content by β-carotene bleaching and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay systems. The results showed that the antioxidant activity of ethanolic extracts of propolis (EEP) samples gradually increased with increasing concentration of the extracts in the concentration range tested. The EEP by HHPE have the same relatively strong antioxidant activities as that by leaching at room temperature (LRT). LRT usually needs 7 days, while HHPE needs only 1 min. From the viewpoints of extraction time, and strong antioxidant activity of its extracts, HHPE was more effective than the conventional extraction methods studied.