Al(Ⅲ) complexes with flavonoids luteolin and baicalein in ethanol were synthesized and characterized using ultraviolet visible spectrometry，infrared spectrometry and mass spectrometry.The molar ratio method and mass spectrometry were applied to ascertain the stoichiometry ratio of the flavonoid metal complexes.Both of the methods indicated a 1〖DK〗∶2 (metal/ligand) composition for the two complexes.Spectroscopic data suggested that coordination reaction occurred in the 4-carbonyl-5-hydroxyl groups and the 3’,4’-dihydroxyl groups for luteolin Al(Ⅲ) complex，and 4-carbonyl-5-hydroxyl groups and 6,7-dihydroxy groups for baicalein-Al(Ⅲ) complex，respectively.Specifically, as the center, Al(Ⅲ) coordinated two molecules of flavonoid to form one five membered ring and one six membered ring using tetra coordinate complex. Antioxidant abilities of the free ligands and complexes were also investigated under an electrochemical point of view. Both the ligands and complexes has scavenging effects on DPPH，hydroxyl and superoxide radicals.Overall，the avonoid metal complexes are more effective antioxidants than the free avonoids.
