Compared to traditional blood glucose monitoring (TGM), CGM can accurately capture asymptomatic hyperglycemia and hypoglycemia events that are missed by TGM, accounting for 33% and 90% of cases, respectively. Real-time CGM provides instantaneous glucose levels and can also generate alarms for hypoglycemia and hyperglycemia based on preset glucose ranges, assisting patients in making timely adjustments to their glucose levels. Clinical studies have found that glucose control guided by real-time CGM is better, and the decrease in glycosylated hemoglobin levels is positively correlated with the frequency of CGM use. More importantly, although glucose variability can be calculated using conventional blood glucose measurements taken every four to six hours, to further assess precise changes in glucose levels, more detailed and accurate continuous data are required. In this respect, CGM has unparalleled advantages over traditional blood glucose monitoring.While the use of CGM in critically ill patients is still controversial.