Objective: To investigate the effect of hyperbaric oxygen therapy (HBOT) on the iNOS mRNA-iNOS-NO signaling pathway and neurofunction protected in a rat spinal cord injury model. Methods: A total of 36 Sprague-Dawley rats were randomly divided into 3 groups: control group (n=12), SCI group (n=12) and SCI + HBOT group (n=12). SCI + HBOT group In the SCI group and SCI + HBOT groups, SCI was performed on rats. In the SCI + HBOT group, rats with SCI underwent HBO treatment 30 min after SCI for 24 sessions. After HBO therapy, measurement of motor evoked potential (MEP), Basso, Beattie, Bresnahan (BBB) scoring and pathological examination were done. RT-PCR and immunohistochemistry were employed to detect the mRNA and protein expression of iNOS, respectively. Diazo colorimetry was performed to detect the serum NO content. Results: The mRNA and protein expression of iNOS in the spinal cord and the serum NO content were markedly increased in the SCI group as compared to the control group (P<0.05). However, the mRNA and protein expression of iNOS and the serum NO content were dramatically reduced in the SCI + HBOT group as compared to the SCI group (P<0.05). Conclusion: HBO therapy can promote the neuroprotection following SCI, which may be related to the effect of HBO on the iNOS mRNA-iNOS-NO signaling pathway.