This study was performed at the whole year in 2015 at 9 sampling sections of Lake Chaohu, aiming to analyze the temporal and spatial variation of the phytoplankton function groups. A total of 15 kinds of phytoplankton function groups were identified:C, N, P, MP, S2, X1, X3, Y, F, J, H1, H2, LM, M, W1. The phytoplankton function groups was dominated by H2 based on the dominant degree(≥ 0.02) and significant differences were found on phytoplankton function groups across 9 sampling sections in the twelve investigations, which mainly consisted of Anabaena, the second was M, which was mainly composed of Microcystis. Particularly, these two communities were characterized by the eutrophication. The successional routine of dominant phytoplankton function groups in different months could be summarized as follow:H2+Y in January, to H2+J in February, to H2 in March, to H2+F in April, to H2 in May, to M in June, to M+H2 in July, to M in August and September, to H2+M in November, to H2 in December. RDA was used to explore the relationship between phytoplankton function groups and major environmental factors. The results showed that temperature, total soluble phosphorus, total nitrogen solubility, permanganate index and water depth were the most important factors influencing the temporal and spatial distribution of phytoplankton function groups.