Components of chemical groups in soil humic acids (HA) and fulvic soids (FA) isolated from soils different in fertilization treatment were studied with the aid of infrared spectrum (IR) and 1H nuclear resonance spectroscopy (NMR),and effects of different fertilization treatments on chemical group structure of the humus were explored.The results show that fertilization affected structure and content of soil humus,and aromatization degree and fraction of simple organic molecules in HA isolated from fertilized soils.The effect was greater in Treatment NPK than in Treatment PK.The 1H NMR results show that the relative content of carbonhydrate H of FA is the highest in the treatment of long balanced fertilization(NPK treatment),while the relative content of aliphatic H is higher in Treatment PK.