In this paper,humic acid extracted from different horzons Lou of soil was classified into 7 fractions according to the condensation degree by alcohol fractional precipitation technique,and the properties of the fractions were studied.

• 采用酒精分级沉淀法，按芳构化程度高低将土娄土不同层次胡敏酸分成7个级分，并对各级分的性质进行了研究。