【Objective】In order to clarify the effects of application of biochar on soil CO2 emissions and changes in different forms of organic carbon, soil CO2 emissions and dynamics of dissolved organic carbon (DOC) and microbial biomass carbon (SMBC) were measured after application of biochar under various fertilization regimes.【Method】An incubation was designed to investigate the CO2 emission and dynamics of DOC and SMBC after application of 2% (biochar/dry soil) and 4% biochar under various fertilization regimes (no fertilizer (CK), organic manure (M), inorganic fertilizer (F), M+F). The correlation among DOC, SMBC and CO2 were analyzed.【Result】 In the F and M+F treatments added with biochar, soil CO2 emission rates in the early period (2-8 d) was significantly higher than those without adding biochar, while during the 10-60 d, CO2 release rates in both treatments were no significant differences. In the CK and M treatments, the CO2 emission rates were no significant differences between the treatments with or without adding biochar throughout the incubation. In CK treatment, the cumulative CO2 emission with application of biochar was not differed with that without biochar. In the F and M+F treatments, the cumulative CO2 emissions were significantly increased after application of 2% and 4% biochar (20.6% and 19.8%, 29.9% and 40.7%, respectively). The correlation showed that there was no relationship between DOC/SMBC and CO2 emissions without adding biochar, however, there was an obvious correlation when biochar was applied. 【Conclusion】Soil CO2 emissions did not change when biochar was applied to the unfertilized soil. However, the cumulative CO2 emission increased by application of biochar into the soil with manure application. Furthermore, the increment of CO2 emission was dramatically increased when biochar was applied into the soil with inorganic fertilizers plus manure.