It is of great concerns on some pollutants cumulated in lake sediments to become the source of pollution, under certain circumstances, causing serious harm on overlying water quality. In this research, experiment was designed based on the fact of seasonal hypoxia near sediment-water interface (SWI) in Lake Aha,Guizhou Province. By means of the control of redox potential, together with microbiological activities, it was found that microbiological activities has significant influences on the redox reactions happened around SWI; and the overlying water quality can be changed remarkably, along with the variation of redox potential, including transparency, odor and poUutant contents. The cluster analysis of experimental data demonstrated that two main groups with similar geochemical behavior during diagenesis process, could be sorted as Mn,Ga, SO₄^2-,Cu,Cr,Pb and Co,Ni,Fe, Sc,V, Rb. Finally, the maximum release of some metals when lake water turned to hypoxia, were calculated, of which plenty of Fe and Mn found can be released into overlying water.