Stress hyperglycemia is a common metabolic disturbance observed in critically ill patients during the perioperative period. However， the use of a single blood glucose measurement is susceptible to various confounding factors and may not accurately reflect the patient's stress status. The Stress Hyperglycemia Ratio （SHR）， an emerging biomarker， is calculated by comparing admission blood glucose levels with the individual's estimated chronic average glycemic level， thereby enabling a more accurate differentiation between stress-induced hyperglycemia and hyperglycemia associated with pre-existing diabetes. Accumulating evidence indicates that SHR demonstrates significant predictive value for major adverse clinical outcomes， including cardiovascular events， mortality， and impaired functional recovery， across diverse critically ill populations such as those with acute myocardial infarction， stroke， and sepsis. Moreover， SHR has been shown to outperform traditional single blood glucose measurements in terms of prognostic accuracy. This review aims to systematically summarize the current evidence regarding the predictive utility of SHR in risk assessment for adverse outcomes among critically ill patients. By enhancing our understanding of SHR's clinical relevance， this review seeks to provide insights into novel approaches for risk stratification， individualized patient management， and ultimately， improved clinical outcomes.