Clarifying the vertical differentiation characteristics of soil carbon (C), nitrogen (N), phosphorus (P) , and their ecological stoichiometry along the water level elevation under the periodic flooding-emergence conditions is beneficial to the soil nutrient management in the water level fluctuation zone(WLFZ). In this study, the typical riparian zone  of the Three Gorges Reservoir was taken as the research area. Soil samples were collected at depths of 0-10, 10-20, and 20-30 cm at water level elevations of 145-155, 155-165, and 165-175 m, with the unflooded grassland at elevation of 180 m as the upper limit. Soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), pH, soil bulk density (SBD), soil water content (SWC), soil mechanical composition, and agglomerates were analyzed. The purposes of this study was to explore the ecological stoichiometric characteristics of soil C, N, and P at different water level elevations and soil layers and to identify the influencing factors. The results showed that: (1) Change of water level elevation affected the soil C, N, and P contents. The mean values of SOC, TN, and TP in the WLFZ were 8.70, 0.79, and 0.63 g/kg, respectively, which were lower than those in the unsubmerged area. With the increase of water elevation, the soil SOC and TN contents increased, and TP content decreased, and the nutrient contents of the surface soil were higher than those of other soil layers. (2) The mean values of soil C/N, C/P, and N/P were 11.67, 15.37, and 1.47, respectively, where C/N and C/P were higher than those of the unsubmerged area and N/P was lower than that of the unsubmerged area. As the water level elevation increased, soil C/N decreased and C/P and N/P increased. There existed a good coupling relationship between soil C, N and P. Nitrogen might be the limiting soil element in the WLFZ, and there was a risk of nitrate leaching. （3) Correlation analysis showed that soil physicochemical properties significantly affected the contents of soil C, N and P (P<0.05), thus regulating the ecological stoichiometric characteristics. Of all the influencing factors, soil pH, bulk density (SBD), and water-stable agglomerate composition were the main ones, followed by soil water content (SWC) and particle size distribution. These findings implied that the periodic flooding-emergence process leaded to the reduction of soil C, N, and P contents and further affected their stoichiometric ratios in the WLFZ. Therefore, in the future, the configuration of soil conservation measures and nutrient adaptations should be adopted according to the spatial distribution patterns of soil C, N, and P ecological stoichiometric characteristics at different water level elevations. This study was expected to provide a scientific basis for soil erosion control and vegetation restoration in the WLFZ of the Three Gorges Reservoir.