Abstract: Humus is the main composition of soil organic matter (SOM), and it plays an important role in carbon sequestration, soil structure, nutrients retention and biogeochemistry cycle. In this paper, we studied the effects of long-term fertilization on soil fulvic acid (FA), humic acid (HA) and humin (HM) in farmland of five soil organic matter levels.The results showed that in arable Mollisols of five organic matter contents, FA, HA and HM increased with the increasing of SOM, and long-term fertilization could increase the contents of FA, HA and HM in soil of different SOM levels, and FA showed significant difference (P<0.05). The correlation analysis showed that the contents of FA and HA were significantly and positively correlated with soil organic carbon, total nitrogen and total phosphorus, but significantly and negatively correlated with soil pH value(P<0.05). Moreover, HM was not significantly correlated with soil organic carbon, total nitrogen and total phosphorus(P>0.05).