The seasonal variations of phytoplankton community and their correlation with environmental factors in subtropical Huangcun reservoirs basin were investigated in this study. A total of 51 phytoplankton species were identified, in which 35.29% of Chlorophyta, followed by 29.41% of Bacillariophyta, and 21.57% of Cyanophyta. In terms of the seasonal composition of community, Cyanophyta was dominant in spring and summer, accounting for 62.96% and 71.03% of the abundance, respectively. While Bacillariophyta was the most abundant group during the fall and winter, with an average contribution of 56.1% and 80.74% to the abundance, respectively. The main dominant species in Huangcun reservoirs basin were Chroomonas acuta and Achnanthidium sp., which occurred in four seasons and were common dominant species. The diversity indices indicated that the basin was in mesotrophic condition. The water temperature, conductivity and nutrients were the environmental factors having the greatest influence on the phytoplankton community composition.