Abstract: The full operation of the Three Gorges Dam Reservoir (TGDR) on the Yangtze River, China, has formed a hydro-fluctuation belt with an annual change in water level of almost 30 m and spanning an area of 350 km². These large changes in the water level have led to a direct decline in the plant community within the hydro-fluctuation belt. Revegetation is an environmentally friendly measure to restore the ecological integrity of the hydro-fluctuation zone in the TGDR, and is also crucial for maintaining sound riparian ecosystem function and services. The study site (107°32'-108°14' E, 30°03'-30°35' N) was located in the Ruxi River basin in Gonghe Village, Shibao Township, Zhong County, in the Chongqing municipality of China. We monitored the changes in soil fertility and quality upon revegetation of Cynodon dactylon in the hydro-fluctuation belt of the TGDR. Plots of C. dactylon grassland at three elevations (150, 160 and 170 m above sea level) in Zhong County in the TGDR were sampled and the contents of soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), and soil microbial biomass phosphorus (SMBP) were determined. The results showed that: (1) The soil microbial biomass at each elevation was significantly higher in C. dactylon grassland than in unplanted soil, indicating that artificial vegetation restoration had significantly increased the soil microbial biomass; (2) The SMBC and SMBN were significantly higher at 160 m elevation than at 150 m and 170 m elevations, but the SMBP was significantly lower at 160 m elevation than at 150 m and 170 m elevations. Thus, special attention should be paid to the transfer of P into water. (3) At the different altitudes, the ratio of SMBC/SMBN ranged from 5.32 to 15.62, and the ratio of SMBC/SMBP ranged from 7.11 to 19.99. The range of SMBC/SOC (soil organic carbon) was 0.68%-2.57%, the range of SMBN/TN (total nitrogen) was 0.68%-3.33%, and the range of SMBP/TP (total phosphorus) was 1.95%-5.23%. The SMBC/SMBN and SMBC/SMBP ratios were significantly higher in C. dactylon grassland than in unplanted soil, indicating that there was more available nitrogen and available phosphorus in C. dactylon grassland than in unplanted soil. In addition, the soil turnover rate was faster in the C. dactylon grassland than in unplanted soil; (4) Soil microbial biomass was significantly correlated with soil organic carbon, total nitrogen, and soil moisture, but was negatively correlated with soil pH. Our study showed that the physical and chemical properties of soil under revegetating C. dactylon significantly affected the soil microbial biomass. Thus, revegetation of C. dactylon increased the soil microbial biomass and also enhanced soil quality in the hydro-fluctuation belt of the TGDR.