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The relationship between community biomass of spring Carex and Sentinel- 2 derived vegetation indices (VIs) was analyzed using regression analysis in one of dish-shaped lakes (i.e. Changhuchi) of Poyang Lake. In addition, the effects of elevation, water level, and temperature changes on community biomass were also examined. The results showed that: ① Among the 10 commonly used VIs, Soil Adjusted Vegetation Index (SAVI) is the most appropriate VI for spring Carex biomass estimation of Changhuchi Lake from March 22ndto May 5th. The cubic polynomial parameterized by SAVI was an optimal biomass estimation model with the root mean square error of 73.91 g/m2 and the predicted coincidence of 71.90%. Spatially, the biomass of spring Carex community generally increased from the central part to lakeshore. ② On March 22nd (normally in the middle of growth) and May 5th (the end of growth), the total aboveground biomass of spring Carex grass was 1.06×105 kg and 3.28×105 kg, respectively, along with the biomass per unit area of 77.56 g/m2 and 208.44 g/m2, respectively. Our estimates were basically in line with the previously reported upper limit of 300 g/m2 in other sub-lakes within Poyang Lake. ③ The growth of spring Carex in Changhuchi Lake is jointly affected by elevation, water level and air temperature. At the end of March, the area below 13.47 m (Yellow Sea Datum) in Changhuchi Lake is generally flooded, hence with dwarf plants and less biomass accumulation. For the regions above 13.47 m, the biomass is also at a low level due to low temperature and short dormancy. As the temperature rises, the biomass of spring Carex in the whole exposed area of Changhuchi Lake gradually accumulates with larger per unit area biomass at the higher elevations. [ABSTRACT FROM AUTHOR]