Postoperative complications are common after major surgical procedures, leading to increased morbidity and mortality. Regional cerebral oxygen saturation (rScO2) reflects cerebral and global perfusion, and thus it can be used to guide hemodynamic management. We aim to explore the effect of rScO2-guided blood pressure management strategy on postoperative major complications in older adults who undergo major noncardiac surgery. This randomized controlled clinical trial includes a total of 400 elderly patients receiving major noncardiac surgery and general anesthesia. Patients will be randomized (1:1) to one of two blood pressure management groups: a standard care group (targeting mean arterial pressure >65 mmHg or within 20% of baseline value), and a rScO2-guided group (absolute value of rScO2 >60% or decrease in rScO2 <10% of baseline). The primary outcome is the composite outcome of major complications (including infectious, respiratory, neurologic, cardiovascular, renal, thromboembolic gastrointestinal, and surgical complications) and deaths within the first 7 days after surgery. Secondary outcomes include the individual components of the primary outcome by day 7 after surgery and 30-day mortality. Data will be analyzed in the modified intention-to-treat population. This study will provide evidence for improving postoperative outcomes using the rScO2-guided blood pressure management among older adults who undergo major noncardiac surgery. Chinese Clinical Trial Registry (Identifier: ChiCTR2200060816).