In order to realize the process mechanism that Shewanella oneidensis(S. oneidensis) reduced uranium(VI), and improve its reduction effect, the reduction mechanisms of uranium with S. oneidensis were studied by FTIR, SEM, EDS. The results show that after the S. oneidensis reduction of U(VI), the cell surface morphology is changed, the gaps and caverns on S. oneidensis surface decrease and more uncrystalmini grains through electron appear, which are binding each other. Much of new crystal structures were generated on the surface of cell. K+ and PO43+ were involved in the process of U(VI) reducti...