Objective:To investigate the causes and preventive measures of critical patients' hypoglycemia.Methods:Using a methodology that is reviewing and analyzing the hypoglycemia of critical patients in our department in recent years.Results: The result shows that drug-induced hypoglycemia is more frequent than non-drug-induced hypoglycemia while asymptomatic hypoglycemia is more frequent than symptomatic hypoglycemia.it is important to implement the continuous glucose monitoring in critical patients.Conclusion:To discover and correct Hypoglycemia in time and avoid abnormal impact.