The aim is to investigate the changes of Connexin43(CX43) in mice serum after Co-60 γ irradiation and its practicability as a biodosimetry. The content of CX43 protein in mice serum was detected using surface plasmon resonance(SPR) technique. Western Blot method was also used as reference. Expression of Connexin43 is sensitive to γ radiation. Obvious up-regulation of CX43 expression was observed by γ-rays doses as low as 0.6 Gy. CX43 protein in mice serum first increased and then decreased with the increasing time after mice were irradiated at dose of 1.2 Gy. The highest level of CX43 appeared 3 h after irradiation. At this moment, the content of CX43 showed a linear correlation with the γ-rays doses in the range of 0−2.4 Gy, however it began to reduce when the dose continued to increase. Western blot results showed that, the fluorescence intensity of the 1.2 Gy group is higher than that of the 0.6 Gy group, and both of them were significantly higher than that of the control group. Detection of Connexin43 protein in mice serum using SPR technique is expected to be a new biodosimetry.Cited