Abstract: Sediment samples and concentrated green algae from Taihu Lake were used as experimental materials for indoor column culture. Under the influence of algae decomposition, the dynamic variations of pH, dissolved oxygen（DO）, total phosphorus（TP）, total dissolved phosphorus（TDP） and active phosphate(PO₄^3-) in overlying water were studied. The results showed that the death rate of green algae in anaerobic culture was faster than that in aerobic culture. The process of algal death gradually consumed oxygen, produced carbon dioxide and even released small molecular organic acids, which made the DO and pH in overlying water of "algal anaerobic" group decrease obviously. During the column culture period（1-20 d）, the concentrations of PO₄^3- and TDP in overlying water of "blank aerobic" group increased significantly, indicating that parts of sediment phosphorus were released into the overlying water under aerobic culture environment. Whereas PO₄^3- concentrations in overlying water of "algae aerobic" group only increased within 10-20 d, which was mainly caused by phosphorus release from algae decomposition in the later stage of column culture. Relatively, PO₄^3- and TDP concentrations in overlying water of "algal anaerobic" group in the 10-20 d changed little. These may be related to the adsorption of PO₄^3- by algae residue and suspended matter in overlying water during the later stage of column culture, which needed further study. The study indicated that green decomposition could obviously reduce DO, pH in water and release phosphorus into water, but there were some differences in the period of phosphorus release under different culture conditions.