Cerebral autoregulation (CA) is an important mechanism to maintain the relative stability of cerebral blood flow and keep the balance of cerebral oxygen supply and demand. However, different individuals in different states have distinct CA capacity and regulation ranges. Identifying patients' CA capacity is helpful for evaluating patients' prognosis; maintaining patients' mean arterial pressure (MAP) in CA range, helps maintain the perfusion of vital organs. However, currently, there is no ideal monitoring method for CA monitoring in patients. The change of non‑invasive regional cerebral oxygen saturation (rSO2) is similar to the change of cerebral blood flow, which is beneficial to non‑invasive real‑time continuous monitoring blood flow in clinical practice. This review intends to describe the research advances on the principle, clinical application [including perioperative period, intensive care unit (ICU), and children], and deficiencies of rSO2 in CA monitoring and aims to discuss the main problems existing in the research and clinical application of rSO2 for CA monitoring and future development directions.