The uranium removal tests of inactivated and non-inactivated Lactobacillus plantarum were carried out under different pH and biomass concentration conditions, and the mechanism of uranium removal by Lactobacillus plantarum was discussed. Based on SEM-EDS, FTIR, XPS, and XRD, the microscopic mechanism of the interaction between uranium and microbial cell surface and the characteristics of sediments on the cell surface were analyzed. The ability of Lactobacillus plantarum to adsorb uranium was significantly improved after heat inactivation. With the pH 6.0, 37℃ and the 10mg/L U(VI), the removal efficiency of U(VI) by heat-killed cells was up to 94.7% during 120min, while the removal efficiency was only 88.9% by live cells. The inactivated bacteria had higher uranium adsorption capacity. At the biomass concentration of 0.06~0.24mg/L and pH value of 3.0~7.0, the rate(W) of accumulative capacity of U(VI) of inactivated bacteria to that of living bacteria is greater than 1. SEM-EDS、FTIR result illustrated the U(VI) could be adsorbed or coordinated on the surface of the active and inactivated cells through functional groups such as hydroxyl, acyl and carboxyl groups. There were 4 distinct crystal peaks of uranyl phosphate compound at 2θ(18.023, 25.492, 27.343 and 40.813°) in the XRD spectrum of living bacteria, while no crystal peaks in the spectrum of inactivated bacteria. XRD result indicated U(VI) can be precipitated with the form of uranyl phosphate by biological metabolism of live cells. There were the peaks attributed U(IV) at U 4f 7/2 with binding energy of 381.20eV and U 4f 5/2 with 390.95eV in the XPS energy spectrum of living bacteria. While There was no the peaks attributed U(IV) in the spectrum of inactivated bacteria. XPS result indicated that U(VI) can be induced to U(IV) by living bacteria.