Abstract: To study the relationship between lake eutrophication and rotifer species, from July 2005 to June 2006, we studied the community structure of rotifers in five lakes of Anhui, including Longwo Lake, Jinghu Lake, Tingtang Lake, Fengming Lake and Yinhu Lake. We evaluated the eutrophication level of the lakes by evaluating a comprehensive Trophic Level Index (TLI_C), as well as the relationship between TLI_C and species diversity (as measured by Shannon-Wiener index, Margalef index, and Simpson index). A total of 79 rotifer species were collected, belonging to 31 genera and 18 families. The results showed that rotifer species num-ber differed significantly in the five lakes with different eutrophication levels (P<0.01). A strong negative correlation between rotifer species number and TLI_C (r=–0.984, P<0.05) was detected, except in Longwo Lake. Lake eutrophication increased the total density and dominance of the most dominant species of rotifers, but decreased community evenness and species diversity.