Carbon monoxide poisoning delayed encephalopathy refers to carbon monoxide poisoning after about two months, after the patient’s symptoms have improved and the patient is conscious, then after a period of pseudo-healing, the patient suddenly shows signs of dementia, accompanied by psychiatric symptoms, such as abnormal personality, temperament, irritability, etc. There may also be extrapyramidal reactions, tremors of the limbs, increased muscle tone, mask face. In severe cases, the patient may exhibit a decortical state and become unconscious. If a cranial magnetic resonance examination is performed, the white matter of the patient can be found to be demyelinated, especially the pallid globules can appear symmetrical high signal, which is a typical imaging change of carbon monoxide poisoning delayed encephalopathy.