A comprehensive study on hydrobicxs and functions of water bodys of four lake areas with different trophic states in Donghu Lake (Wuhan) was carried out during Jan. 1991-Aug. 1993. The four lake areas differ greatly in the characteristics of aquatic organisms. The maximum values of HBC, FC, algal cell density and primary production, individual density of zooplankton and zoobenthos were found at Chagangwan area, and the minirmim values were observed at Niuchaohu area. According to all of the bio-parameters, trophic levels and states of water uses of the studied 4 lake areas, their functions are as follows. Chagangwan area is suitable for receiving and purifying waste-water; Guozhenghu area is suitable for flood control, recreations and tourist trade; Houhu area and Niuchaohu area are suitable for waterworks and tourist trade respectively.