The tannins from bark and leaf of Eucalyptus Grandis x E.Urophylla were purified by NKA-9 macroporous resin, the antioxidant activities were evaluated from the scavenging activities of 1,1-diphenyl-2 -picrylhydrazyl radical (DPPH•) and hydroxy radical (•OH), and the antimicrobial activities against 5 food-borne pathogenic bacterium were tested by the disk diffusion method. When the conditions for dynamic purification were loading of 0.8 g/L sample solution with 10 mL, and complete desorption with 3 BV of 80% ethanol, the mass fraction of bark tannins purified products was 47.82%. When the conditions for dynamic purification were loading of 0.5 g/L sample solution with 10 mL, and complete desorption with 3 BV of 80% ethanol, the mass fraction of tannins purified products from leaf was 37.00%. IC50 values of the purified tannins of bark and leaf on DPPH· scavenging effect were 0.0119 and 0.0121g/L, respectively. When the concentration was 0.5g/L, the scavenging rates on ·OH of the purified tannins of bark and leaf were equivalent to 2.55 and 2.19 times of VC, that of VC was 24.20%. The antimicrobial activities of purified tannins against Escherichia coli, Staphyloccocus aureus, Shigella, Salmonella, Bacillus cereus were better than the crude extracts, and the diameter of antibacterial zone of purified tannins of bark and leaf against Shigella were 13.25 and 12.50mm.