Cerebral ischemia refers to the lack of blood supply in all parts of the brain leading to brain tissue ischemia and hypoxia, which leads to irreversible damage and necrosis of in dense ischemic areas. Its high disability and high mortality rate will cause serious harm to patients and their families. The key to the prognosis of cerebral ischemia is to take some measures to restore blood flow and oxygen supply, control the size of the infarct and save the cells in the penumbra. Hyperbaric oxygen therapy refers to letting patients inhale 100% oxygen under the environmental pressure higher than one atmosphere absolute to increase the oxygen content in the body. It can provide enough oxygen for ischemic hypoxic brain tissue and prevent the further aggravation of injury. Clinical trials have demonstrated that hyperbaric oxygen therapy can improve motor, sensory and cognitive dysfunction in patients with cerebral ischemia and can also be used as an adjuvant therapy. The mechanisms of hyperbaric oxygen therapy in the treatment of cerebral ischemia mainly include increasing the oxygen content, inducing neuroplasticity, regulating cerebral blood flow, regulating the expression level of cytokines, and reducing oxidative stress. It is worth noting that there are some prominent problems in the current research, such as adverse reactions during treatment, uncertainty of the effective therapeutic time window, a certain degree of difference between the results of basic research and clinical research, and the unportability of hyperbaric oxygen chamber. These problems severely limit the clinical application of hyperbaric oxygen therapy. In the future more basic and clinical research are needed to develop a more secure and reliable hyperbaric oxygen therapy protocol, reduce the toxic side effects and adverse reactions that may occur during the treatment, and provide new ideas for the treatment and prognosis of patients with cerebral ischemia