Abstract: The photocatalysis is an efficient method to remove Cr(VI) from aqueous solution. Compared with adsorption, which can reduce Cr(VI) to Cr(III) in a short time. Glutaraldehyde was used as a crosslinking agent to graft thiourea onto sodium alginate (SA) for the synthesis of thiourea/sodium alginate beads (GTSA), the adsorption and reduction mechanism of Cr(VI) in solution under light condition was investigated. Compared with SA, the light absorbance of GTSA is greatly increased, as well as the ability to adsorb and reduce Cr(VI). Under the irradiation of ultraviolet mercury lamp at pH=1, the removal rate of Cr(VI) reaches 99%, and the reduction rate reaches 79%. The mechanism of Cr(VI) adsorption reduction by GTSA was analyzed by FTIR, SEM, UV-DRS and XPS, which indicated that the removal process of Cr(VI) is a synergistic effect of electrostatic adsorption and photocatalytic reduction.