Objective To investigate the protective effects and mechanism of hydrogen-rich saline against γ irradiation-induced injury in kidney epithelial HK-2 cells. Methods HK-2 cells were divided into 4 groups: the control group, the hydrogen-treated group, the irradiated group, and the irradiation plus hydrogen-treated group. The hydrogen-treated group and the irradiation plus hydrogen-treated group were pretreated with 5 mL hydrogen-rich solution while the control group and the irradiated group with 5 mL non-hydrogen PBS for 10 min, then the irradiated group and the irradiation plus hydrogen-treated group were simultaneously treated with γ-irradiation (6 Gy) for 325 s. The malondialdehyde (MDA) changes were determined by clorimetric method, and the hydroxyl radicals(·OH) were examined after being incubated with HPF for 15 min at 37℃. Flow cytometry was used to observe the apoptosis rates of HK-2 cells 24 h after irradiation, and the cell survival was examined by clonogenic assay every 24 h until the 10^th day. Results Hydrogen-rich saline significantly improved the survival of HK-2 cells at the 10^th day after 6 Gy irradiation(P<0.05), and significantly decreased the apoptosis rates of HK-2 cells (P<0.01). It was also found that hydrogen-rich saline significantly down-regulated MDA level (P<0.05) and ·OH level in irradiated HK-2 cells (P<0.05). Conclusion Hydrogen-rich saline has a protective effect against γ-irradiation-induced injury in HK-2 cells.