Abstract: The content of soil carbon is an important indicator for the evaluation of soil quality, it could significantly affect the physical, chemical, and biological properties of soil. The increase of soil carbon content not only contributes to the sustainable development of agricultural production, but also plays a vital role in maintaining the cycle of the earth ecosystem. The author studied the effects of biology humic acid, which was extracted from the tunning of organic waste, on the component of soil carbon. The results showed that humic acid and organic fertilizer could significantly increase the content of soil total organic carbon to a certain extent. The treatment of humic acid chemical fertilizer could maintain soil organic carbon content in a long time (10-40 d), and the soil organic carbon content increased by 1.6%-10.5%. The contents of soil water soluble organic carbon were different in different fertilizer treatments, compared with CK, the soil water soluble organic carbon content increased by 2.7%-20.1% in the treatment of humic acid chemical fertilizer. Fertilization treatments could maintain the content of soil microbial biomass carbon, which was significantly higher than that of CK under humic acid content of 400 mg/kg.