Malnutrition refers to the state of energy or nutrient deficiency caused by insufficient intake or utilization, which is the main factor leading to adverse clinical outcomes. In order to further standardize the nutritional support treatment process, nearly 100 experts in related fields were organized by the Chinese Society of Parenteral and Enteral Nutrition (CSPEN) to elaborate on the following topics based on the existing evidence-based medical evidence: nutritional screening and assessment; diagnosis and monitoring of malnutrition; diagnosis and treatment process, energy targets and health economic benefits of nutritional support therapy; indication, starting time, infusion mode and formula selection of enteral nutrition (EN) and parenteral nutrition (PN); monitoring of tolerance of nutritional support treatment, prevention and management of complications, etc. Finally, 37 questions and 60 recommendations were put forward to provide reference for clinical standard application of parenteral and enteral nutrition.