Abstract:The effects of water flow under different light intensity on the growth of Microcystis aeruginosa were studied to elucidate the mechanism of water bloom. The experiment was conducted at a light intensity of 2 500 lx and 3 500 lx in a small perspex ring groove,which generated water flow under axenic condition and constant temperature and light. The results showed that the adaptation growth time of Microcystis aeruginosa increased, the exponent growth time was extended and the growth ratio was improved by water flow, which directly influenced the density of algae, and that the effects of water flow on the growth of Microcystis aeruginosa were related to light intensity. The light intensity at 2 500 lx was more conducive to the growth of Microcystis aeruginosa than that at 3 500 lx, the optimal water flow was 35 cm/s both for the light intensity of 2 500 lx and 3 500 lx. There were no significant differences among different water flow at the intensity of 2 500 lx. Therefore, there are not significant differences at 3 500 lx. The light intensity requirement was decreased and the efficiency was increased by water flow.