From December, 2004 to May, 2005 phytoplankton was investigated monthly in the process of the aquatic vegetation rehabilitation in Lake Yuehu, Wuhan. The result indicated that, under the condition of high nutrition concentrations, phytoplankton was still maintained at low biomass and density; phytoplankton growth was positively correlated with the temperature, but not with nutrient concentrations. Potamogeion cripus and Elodea canadensis made water body maintain higher transparency. Phytoplankton was mainly composed of cryptophyta and diatom. The typical species of water bloom didnt appear with the increase of temperature. The phytoplankton community structure was possibly changed by existence of these two submerged macrophytes. Therefore, rehabilitation of aquatic vegetation was the effective way to control the eutrophication of the lake in winter and spring of lower temperature.