Early initiation of enteral nutrition (EN) has been the unanimous recommendation and routine use of nutritional therapy in critically ill patients. However, there are risks of reflux, aspiration, feeding intolerance (FI), bloating, diarrhea and even intestinal ischemia and necrosis during the implementation of EN, which can prolong hospital stay and even lead to poor outcomes. Gastrointestinal function is a critical component in implementing EN in critically ill patients. Currently, the most commonly used indicators to evaluate the effectiveness of EN implementation include gastric residual volume (GRV) and gastrointestinal symptoms, etc. However, the threshold for monitoring and diagnosing GRV is still controversial, and there are no reliable indicators of gastrointestinal function. In recent years, with the development of bedside ultrasound technology, it has been widely used in clinical practice for its advantages of being bedside, non-invasive, visualization, immediate and reproducible. Bedside ultrasound is a reliable and promising tool, it can be used not only to evaluate the structure, function, and blood flow of the gastrointestinal tract but also to guide the implementation of EN, monitor FI, guide the placement of nasogastric tubes, and evaluate nutritional status. Therefore, this paper will addresse the advantages and possible pitfalls of bedside ultrasound in the implementation of EN.