OBJECTIVE: To investigate the MRI plain and diffusion-weighted (DWI) and its hydrogen proton spectroscopy (1HMRS) manifestations after CO poisoning (COP) after gas explosion. MATERIALS AND METHODS: GE 3.0T MRI plain, DWI and 1HMRS scans were performed in 15 patients who developed symptoms after gas explosion, and 7 of the more severe patients were followed up for review after treatment. RESULTS: All 15 patients had headache and nausea with dizziness; 7 patients had symptoms of memory loss, abnormal judgment, amnesia, and cognitive impairment. MRI plain scan showed extensive brain changes, with the highest rate of abnormalities in the pallidum, the nucleus accumbens, and the caudate nucleus in the basal ganglia structures. For patients with milder symptoms, cortical swelling was the main manifestation, and DWI showed areas more obvious than plain scan. Abnormal lactate (Lac) waves were seen in all cases of 1H MRS, and five of them showed decreased N-acetylaspartate (NAA) and increased choline complex to creatine ratio (Cho/Cr) at some sites. The NAA, Cho/Cr and Lac were normalized with the improvement of clinical symptoms and the decrease of cerebral edema, and the recovery was slower in the sites with lower NAA and more pronounced Cho elevation. Conclusion: MRI scan, DWI and MRS can reflect the brain parenchymal manifestations of CO poisoning in the early stage. In the early stage of COP, the white matter of the brain is more sensitive to hypoxia than the gray matter, and DWI reflects the brain parenchyma more early than MRI plain scan; while in the late stage of COP, the changes in the basal ganglia area only appear, and MRS reflects the repair of brain tissue earlier than MRI plain scan after treatment.