Based on in situ data from Chaohu Lake, a novel algorithm was developed to estimate POC concentrations in eutrophic lakes. This two-step algorithm examined changes in absorption aph(665) and associated to POC concentrations though a measured relationship between aph(665) POC determined in extensive measurements in this large eutrophic lake. Two different aph(665) algorithms were explored. While both provided good estimates of POC concentrations, Gons algorithm (RMSErel=2190%) was superior to that of Simis (RMSErel=23.81%). This approach was developed for medium-spectral resolution satellite senors, such as MERIS or Sentinel 3-OLCI. The application of this approach will provide new insights to our understanding of the aquatic carbon cycle in inland waters.