Clinically, methane is an anti-inflammatory gas used to treat organ damage. There is no extensive research on methane's repair of traumatic brain injury (TBI), so this study aims to investigate the role of methane and its potential mechanism. A rat TBI model was established by mechanical impact. SD rats were divided into four groups, including sham group, TBI group, 2 or 20 mL/kg methane-rich saline (MS) group. Morris water maze test revealed that MS improved cognitive function in TBI rats. HE and Nissl staining showed that MS reduced the blurring of brain tissues boundary, the number of necrotic plaques and neurons in TBI rats. In addition, ELISA revealed that MS restored the oxidative stress of TBI rats and reversed the inflammatory effect of TBI on brain cells, and TUNEL staining detected that MS inhibited cell apoptosis. Western blotting showed that MS downregulated Caspase-3 and Bax protein levels and upregulated Bcl-2 level. And MS inhibited phosphorylated expressions of Janus kinase 1 (JAK1), signal transducer and activator of the transcription (STAT1) and NF-κb-p65. In conclusion, MS improved cognitive function, reduced inflammatory response and oxidative stress and inhibited cell apoptosis to relieve rat TBI by blocking the activation of the JAK1/STAT1/NF-κb-p65 pathway.