Dissolved organic matter (DOM) from the Huangnitu was studied by means of elemental compositon analysis, FTIR and ¹H-NMR and compared with fulvic and humic acids. Results show that DOM, fulvic and humic acids differ widely. Humic acid has a high content of aromatic unsaturated substances and alkyl hydrocarbons with long branched chains; fuvic acids is characterized by large amount of carboxylic functional group, and DOM consists primarily of carbohydrate, containing a lot of hydroxyl and little of aromatic unsaturated substances.