Delirium is always associated with high mortality, prolonged length of stay in intensive care unit (ICU), post-ICU cognitive impairment, and other adverse outcomes, so that it arouses medical staffs' concerns for critical patients recently. Both Chinese and American Critical Care Associations have published clinical guidelines of delirium management in adult ICU, which make the diagnosis and treatment of delirium standardization gradually. However, there is still lack of attention and researches in pediatric ICU. Assessment or diagnostic tools for pediatric delirium are still inconsistent. Because children's cognition and behavior are different from adults, there is a limit to directly apply the adult delirium assessment tools (e.g. CAM-ICU) to pediatric patients. In this paper, we reviewed the pediatric delirium assessment tools, and summarized the characteristics and applications of these tools (e.g. pCAM-ICU, PAED), in order to provide references to deliver the assessment of pediatric delirium as soon as possible.