Nutritional and metabolic disorders are the common problems in PICU. They often lead to deterioration in child nutrition and vice versa. Reasonable assessment of the energy consumption can provide theoretical basis for proper nutrition support in critically ill children. In this review, the methods of evaluating the energy consumption which included energy metabolism measurement and prediction equations were introduced, and the importance of indirect calorimetry was emphasized. Meanwhile, the research situation of energy consumption assessment at home and abroad and the current status of its clinical application were also reviewed.