The soil in the water level fluctuation zone (WLFZ) has specific particularly physical and chemical properties as well as ecological functions because it is generated in a special hydrological environment. The nutrient content of the soil has a high level of variability in time and space. Therefore, the distribution, migration and transformation of organic matter (OM) are under complex influences. In the present study, a typical WLFZ in Guanting Reservoir, and the temporal and spatial distribution characteristics of OM content in the soil, were analyzed. Results showed that the OM content of WLFZ soil in Guanting Reservoir was fairly low, and changed in the range of 1.64-26g/kg, with an average value of 13.16g/kg. The coefficient of variation was 50.59%, which showed that the distribution of soil nutrients in the WLFZ had higher heterogeneity, because of the dry-wet alternate hydrological conditions and human activities. The OM content of the frequent flooding area was 15.74g/kg on average, which was higher than the contrasting long-term exposed area at 10.12g/kg. The coefficient of variation was 41.38% in the frequent flooding area, which was lower than in the control zones that were 54.98%. This indicated that the soil nutrient retention ability in the frequent flooding area was stronger, and differences of soil OM between different sampling points were relatively small. Under different plant communities, the OM content of Phragmites australis and Typha angustifolia emergent communities was the highest, with an average value of 17.088g/kg; the lowest content was in Populus simonii and Bothirochloa ischaemum mesoxerophytes communities, which had an average value of 9.12g/kg. The Polygonum Lapathifolium and Cirsium setosum hygrophyte communities were second highest, with an OM average value of 15.49g/kg. In different soil depths, the OM content varied, with an overall decreasing trend from the surface downward. The OM of each soil layer showed significant differences (P < 0.05). The soil C/N changed in the range of 1.64-18.95, with an average value of 8.95. This demonstrated that the C/N of the study area was relatively low, the OM had a high degree of humification, organic nitrogen tended to accumulate, there was greater potential of soil anaerobic decomposition to produce CH₄ and CO₂. In the vertical distribution, C/N first increased and then decreased as the depth of the soil profile changed, and reached the maximum value at 30cm deep. Soil OM and total phosphorus, total N, and C/N were significantly positively correlated, with coefficients of 0.62 (P < 0.01), 0.57, and 0.60 (P < 0.05), respectively. This showed that the soil OM, total phosphorus, total N, and C/N had similar change trends, and experienced interaction. Soil OM and moisture were negatively correlated (R=-0.51) at the 0.05 significant P-value, indicating that soil moisture in the study area had a significant impact on the OM content. Temperature had a significant influence on the distribution of soil OM in the study area, the correlation coefficient was -0.508, significance level P=0.031. Vegetation cover and soil OM content was significantly positively related, indicating that the vegetation factor was also an important factor affecting the distribution of soil OM.