The structural features of humic substances were characterized using elemental analysis, infrared spectrometry and thermal analysis techniques. Elemental analysis showed that it was lower and higher aromaticity that carbon content of Na4P2O7-extracted humic acid (NaHA), NaOH-extracted humic acid (PAHA), Na4P2O7-extracted fulvic acid (NaFA) and NaOH- extracted fulvic acid (PAFA) in application vermi-compost compared with control treatment. Thermal analysis suggested that high temperature exothermic peak of PAHA disappeared in application vermi-compost and control treatment compared with NaHA. NaHA had larger thermal stability and mid-temperature exotherm than PAHA. Infrared spectrometry suggested that soil humus from Na4P2O7-extracted and NaOH-extracted humus included a large number of aromatic compounds and aliphatic compounds. In summary, some differences between Na4P2O7-extracted humus and NaOH-extracted humus existed in thermal properties and composition of functional groups.