Abstract: In order to enhance the drug anti-tumor efficacy and biocompatibility, diselenide-hyaluronic acid has been developed as tumor therapy drug under irradiation in this research. In cellular toxicity evaluation, we observed that the introduction of hyaluronic acid had reduced the toxicity of diselenide agent. Under low therapeutic irradiation dose 4 Gy, remarkable anti-tumor effect has been realized, which tumor cellular viability can be realized with the drug concentration of only 27 μg/mL. The diselenide-hyaluronic acid developed in this research can provide an effective tumor therapy protocol under irradiation.