Abstract: Some constituents of the algal blooms and the amount of chlorohpyll α in the sediments of Lake Donghu, Wuhan are investigated. On the basis of the components of the blooms, the contents of C, N, and P in the living algae sunk to the sediments are calculated. A regression is constructed to describe the relationship of carbon-chl α.The average percentage of C, N, and P of the blooms in Lake Donghu, Wuhan is 39.30, 7.98, and 0.94, respectively. The ratios of different components are listed. The dry wt./wet wt. ratio is 0.20, the C/N ratio, 5.10, the C/P ratio, 46.54, and the C/chl α, 133.32.In 1983, the amounts of chl α sunk from the sestom algae to the bottom of the Lake were 43.8675 (Station Ⅰ), and 35.5881 (Station Ⅱ) μg·m-2·day-1 in average. The contents of C, N, and P of the living algae in the sediments, calculated by using the regression of carbon-chl α and the ratios of different components, were estimated at 2.53, 0.50, and 0.05 mg·m-2·day-1, respectively (Station Ⅰ), and 2.09, 0.41, and 0.04 mg·m-2·day-1 (Station Ⅱ).By the method giv.en in this study, the amount of living algal material in the sediment can be discriminated from that of the detritus contained in the same sediment.