The study area locates in the Taihu Basin, and it spans across three provinces (Jiangsu, Zhejiang, Anhui) and the Shanghai Administrative Region. We sampled at 85 sites during Aug. and Sep. 2019, including lakes, rivers, streams and reservoirs, to investigate the effects of spatial and environmental factors on the distribution characteristics of phytoplankton functional groups (PFG) in Taihu Basin. A total of 250 phytoplankton taxa, belonging to 9 phyla, 13 classes, 28 orders, 57 families and 110 genera, were identified by the "artificial intelligence image recognition technology" for the first time, combined with traditional microscopy. The phytoplankton species composition was dominated by Chlorophyta (45.6%), followed by Bacillariophyta (19.2%) and Cyanophyta (16.4%). According to the PFG classification method, 31 functional groups were identified, respectively, with dominant function groups including M, S1, C, D, Y, G, MP, P, J, SN, F, TB, K, H1 and W1. The results showed that: 1) There were significant differences in the PFG composition among different water bodies in Taihu Basin, mainly from M, J, S1, Y, P and H1 groups; 2) The PFG distribution in Taihu Basin showed certain spatial heterogeneous, and three cluster groups were found. Moreover, the corresponding species composition types are Cyanophyta, Cyanophyta-Chlorophyta-Bacillariophyta and Chlorophyta-Bacillariophyta-Cyanophyta. The dominant groups are M and S1 groups, M, S1, P, j groups, P, S1, J, D and C groups, respectively; 3) Spatial factor plays a major role in the formation of phytoplankton community than environmental factor in Taihu Basin. Redundant analysis showed that COD_Mn, NO₃^--N, TN, SD, pH and DO were the main environmental factors affecting the PFG distribution. Over the past decade, the environmental management policy led by source pollution control has achieved remarkable results in the Taihu Basin; however, more effective prevention and control methods are expected to propose for controlling cyanobacterial blooms in the future, and the control of organic pollutants and nitrogen should be paid more attention for aquatic ecological management in Taihu Basin during summer. More importantly, appropriate aquatic ecological management mode should be adopted to deal with different water types and different PFGs.