Abstract: Eutrophication is an urgent problem faced by lake manager，it is necessary to study lake eutrophication and its limited factors for lake management. In order to assess the eutrophic status and understand its influencing factors, field investigation of water quality was carried out at 109 sampling sites in five impounded lakes (Lake Gaoyou; Lake Hongze; Lake Luoma; Lake Nansi; Lake Dongping) in the east route of South-to-North Water Transfer Project in April 2018 (water non-diversion) and October 2018 (water diversion) separately. Water samples were collected for determination of permanganate index (CODMn), total nitrogen (TN), total phosphorus (TP) and chlorophyll a (Chl a), and transparency (SD) was measured in situ．The comprehensive trophic level index TLI (∑) was used for eutrophic status assessment, and multivariate statistical analysis was used to analyze the eutrophication characterization and limited factors. The results indicated that water quality parameters were varied among impounded lakes in the same water period, and water quality of impounded lakes in water non-diversion period was better than that in water diversion period, which were mainly affected by total nitrogen and total phosphorus. The comprehensive trophic level index of Lake Gaoyou, Lake Hongze, Lake Luoma, Lake Nansi and Lake Dongping were 54.43 and 49.74、55.00 and 48.50、54.14 and 38.30、53.41 and 40.57、52.86 and 40.77, implying that these lakes were light eutrophication level during water diversion and mesotrophic level during water non-diversion. The correlation coefficients between TLI and SD and Chl a were -0.51 and 0.46 in water diversion period and -0.73 and 0.82 in water non-diversion period, indicating that SD and Chl a were the limited factors for eutrophication of implouded lakes.