Objective To investigate the protective effects and mechanism of Hydrogen-rich saline against γ irradiation-induced injury in HK-2 cells. Methods HK-2 cells were separated into 4 groups: the contral group, the Hydrogen-treated group, the irradiated group, the irradiated Hydrogen-treated group. The Hydrogen-treated group and the irradiated Hydrogen-treated group were pretreated with Hydrogen-rich solution 10minutes before γ-irradiation of both the irradiated group and the irradiated Hydrogen-treated group at the dose of 6Gy. The apoptosis rates of the HK-2 cells were observed by Flow Cytometry24 hours after irradiation while the survival were examined through the clonogenic assay every 24 hours until the 10th day The malondialdehyde (MDA) and the Hydroxyl radicals(• OH) were examined immediately after γ-ray irradiation. Results Hydrogen-rich salineincreased the survival of HK-2 cells at the 10th day after irradiation of 6Gy (P <0.05), and the apoptosis rates of the HK-2 cells significantly decreased (P<0.01); Hydrogen-rich salinereduced MDA level (P <0.05)as well as • OH level in HK-2 cells. Conclusion Hydrogen-rich saline exert protective effect against γ-irradiation-induced injury in HK-2 cells. © 2014, Second Military Medical University Press. All rights reserved.