Abstract: Characteristics of algal physiological ecology is important for researchers to explore the mechanism of algal bloom outbreak and forecast and prevent algal bloom. Four common bloom algae were taken as research objects, namely Stephanodiscus hantzschii, Cyclotella sp., Scenedesmus obliquus, and Microcystis aeruginosa. The effects of temperature and illumination on the chlorophyll fluorescence of the four bloom algae were studied by chlorophyll fluorescence technology. Results reveal that Stephanodiscus hantzschii has strong adaptability to low temperature with suitable temperature ranging from 3 ℃ to 22 ℃, while high temperature could easily lead to thermal stress. In particular, under suitable temperature, its electron transport rate obviously increases with the increase of illumination, which indicates Stephanodiscus hantzschii has strong light protection and light utilization ability. Microcystis aeruginosa has good adaptability to high temperature with suitable temperature of 15~30 ℃, while blow 10 ℃ it will suffer from temperature stress, and its utilization efficiency of light energy improves with temperature rising. In addition, Cyclotella sp. also shows adaptability to high temperature, while low temperature (3~10 ℃) may cause growth retardation. In comparison, Scenedesmus obliquus displays a wider adaptation to temperature, and shows higher utilization efficiency of light energy and light quantum yield under certain temperature range (22~ 30 ℃). The results show the differences of physiological ecology characteristics of the four algae, and provide reference for the prediction, early warning and management of algal bloom.