With the development of nuclear power, radioactive pollutants discharge into the environment and then contaminate soil and water resources. Nanoscale zero-valent iron (nZVI) materials are widely used in water remediation due to their strong reducibility and high removal efficiency. A carbon-based zero-valent iron material (Fe-CB) was prepared in this work. Fe-CB was fabricated using sodium alginate (SA) as a carbon source via one-step carbothermic method and then applied to eliminate U(Ⅵ) from aqueous solution. Its mechanism and adsorption properties of Fe-CB and U(VI) were studied by spectroscopic analyses and macroscopic experiments. The results illustrated that Fe-CB possessed of ample functional groups (such as -OH and -COOH) and high BET surface area, which made up for the dispersibility and low removal efficiency of nanoscale zero-valent iron (nZVI). The removal of U(VI) by Fe-CB achieved equilibrium in 3 h and the maximum sorption capacity was 77.3 mg·g ^-1 at 298 K. XPS analyses indicated that the U(Ⅵ) removal by Fe-CB was a synergistic effect of reductive adsorptive processes. Adsorption process resulted from surface complexation and the reduction process was dominated by U(VI) reduction to U(IV) by nZVI. The results show that Fe-CB can be used as an inexpensive and highly efficient pollutant scavenger, which has great potential for environment pollution management.