Abstract: Objective:To explore the association of stress hyperglycemia and its control level with the prognosis of critically ill patients.Methods:Seven hundred and ten critically ill patients with stress hyperglycemia were included in the study.The patients were divided into survival group and death group according to the prognosis.The initial blood glucose after admission and the acute physiology chronic health evaluationⅡ(APACHEⅡ) score were compared between the two groups.According to the control level of blood glucose，the patients were divided into group A(4.0-6.1 mmol/L),group B(6.1-10.0 mmol/L) and group C(10.0 mmol/L).The mechanical ventilation time,hospital stay time in ICU,incidence of nosocomial infection,mortality and morbidity of hypoglycemia were compared among different groups.Results:The initial blood glucose after admission and APACHEⅡ score in the death group were higher than those in the survival group(P0.05 and P0.01).The incidence rates of nosocomial infection,mortality and mechanical ventilation time in group A and group B were lower than those in group C(P0.05 to P0.01).The morbidity of hypoglycemia in group A was higher than that in group B and group C(P0.05).There was no significant difference in admission days in ICU among the three groups(P0.05).Conclusions:Stress hyperglycemia and its control level of critically ill patients are correlated with the severity of the disease and the prognosis.