Abstract: Objective　To explore the value of elevated amylase in assessment of severity of the disease and its influencing factors in critically ill children. Method　The clinical data from critically ill children hospitalized in pediatric intensive care unit were retrospectively analyzed from November 2009 to June 2014. According to levels of serum amylase, the critically ill children were divided into normal serum amylase group ( ≤ 103 IU/L) and elevated serum amylase group (>103 IU/L). The differences between two groups were compared. Results　A total of 1920 critically ill children were enrolled, most of whom had primary respiratory and neurological diseases. Among them, 1470 children had normal serum amylase (76.6%) and 450 children had elevated serum amylase (23.4%). The elevated serum amylase group had significantly higher rate of organs failure ( ≥ 4), lower rate of PCIS (<70), higher rate of invasive mechanical ventilation and mortality than those in normal serum amylase group (P<0.001). The correlation of serum amylase with lipase blood, urine amylase, blood urea nitrogen and creatinine were significant (r=0.246 to 0.683, P<0.001). Blood amylase was positively correlated with shock index (r=0.111, P=0.002) and negatively correlated with respiratory failure index (r=0.133, P<0.001). Conclusions　Serum amylase could be used to assess the severity of disease. The elevated amylase was closely related to pancreatic exocrine function, renal function, ischemia, and hypoxia. The elevated serum amylase in critically ill children is a warning sign.