Complex reactions between Cr 3+ and Black Wattle Extract and its oxidizing degraded products (obtained by using 15%,30%and 60% H 2O 2)have been studied and variations of pH and precipitate in these reactions ave also been determined. The results show that(1)The oxidizing degraded products have different complex properties from original extract, and vary with oxidizing degree.(2) The complexes of high oxidizing degraded products with Cr(Ⅲ) have no precipitate in pH 2-12,and they can resist certain alkali; While the complexes of moderate oxidizing degraded products have precipitate, and precipitate rises correspondingly with temperature rises, and varies with different products.(3)Under the same temperature,pH rises with the increase of usage in extract products, and the higher the oxidizing degree of products, the higher pH rises.