Abstract: The influence of fire on wetland ecosystem is a hot topic in the study of the fire ecology and wetland ecosystem at home and abroad. However, the effect of fire on soil carbon components and microbial carbon sequenstration potential in Poyang Lake under water level fluctuation is still not clear. This paper chose the burned (January 15) and unburned area with plant Triarrhena lutarioriparia as the experiment plots, located in the Wetland Natural Preservation Zone at Changhu chi of the Poyang Lake, and 0-10 cm depth soils was sampled at January 18, April 12, and Novermber 10, 2015, to analyze the soil carbon components, soil enzymes and soil bacterial and carbon-fixing microbe activities. Results showed that fire interference had important effects on soil carbon and nitrogen content, soil enzyme activity and different carbon components. For the first sampling time (January 18, 2015), the burned soil easy oxidation active organic carbon content (4.12 ± 0.30 mg/g) was significantly lower than that of unburned soils (16.14±0.17 mg/g) (p < 0.05), and the burned soil microbial biomass carbon (2 359±535 mg/kg) and cbbL gene copies（1.68±0.17×105 copies/g）is significantly higher than those (1 095±110 mg/kg and 4.61±3.12×104 copies/g) (n=3, p < 0.05) of unburned soil, but there was no significant difference in the content of soil soluble organic carbon, soil respiration and soil RubisCO activity (p > 0.05). There was no significant difference in the content of different carbon components, cbbL gene copies, and RubisCO enzyme activity for burned and unburned soils at the next two sample times (April 12 and November 10, 2015). While, the soil microbial biomass C and soluble organic carbon were significantly different during water level fluctuation with a trend from dry, flood to normal water level. Correlation analysis showed that the soil temperature, 16srRNA and cbbL gene copies were negatively significant related to the soil carbon components. The soil easy oxidation active organic carbon and soluble organic carbon were positively related to soil respiration and RubisCO enzyme activity. So the increase of soil temperature was not conducive to the accumulation of soil organic carbon. In addition, the increase of soil carboxylase activity is conducive to the assimilation of CO₂ by microorganisms, thus increasing the content of soil organic carbon components.