Algal blooming in eutrophic lakes has become a critically important issue.As the fifth largest freshwater lake in China, Lake Chaohu has drawn increasing attentions due to the declining of water quality and the occurrence of massive algal blooms.This study applied 2478 free cloud MODIS images onboard Terra and Aqua satellites over the period of 2000-2015 to extract algal blooms with a floating algal index algorithm. The results showed that blooms coverage, frequency, and duration noticeably increased during these years, and the initial blooming occurs earlier. Particularly, algal blooms became more serious during 2000-2015. The conditions for algae blooming was getting better during 2008-2010, and the growth trend has emerged since 2011. 16-year series algal blooms data will help to understand the change in water quality of the Lake Chaohu.