The in vitro antioxidant and the antimicrobial activities of four flavonol compounds (Galangin, Kaempferide, Kaempferol and Quercetin) extracted and separated of Alpinia officinarum Hance rhizomein were studied. The results showed that quercetin had most significant antioxidant activity among the four flavonoids. Moreover, the antioxidant activity of the other three flavonol compounds in order, Kaempferol (highest), Kaempferide, Galangin (lowest). However the ABTS radical scavenging experiment results showed that the antioxidant activities of the three compounds were the same. The further antimicrobial experiment results showed that four flavonol compounds had antimicrobial activity to Staphylococcus aureus. S. aureus and Bacillus subtilis were two of the most sensitive among all the test strains to quercetin, and the MIC and MBC were detected to be 1.25 and 2.5 mg/mL, and 2.5 and 2.5 mg/mL respectively. However, all the four compounds showed very weak resistance against Escherichia coli, P. aeruginosa, Aspergillus niger and Monilia albican.