Hypercapnia respiratory failure is one of the common types of respiratory failure in clinical practice. Traditional oxygen therapy can improve oxygenation, but may inevitable cause some complications. In recent years, high‑flow nasal humidified oxygen (HFNC) therapy has been widely used in clinical setting as a new effective method. It uses high speed of oxygen flow to reduce the anatomical dead space of the mouth, nose and pharynx, reduce CO2 re‑inspiration, produce positive pressure at the end of exhalation, increase expiratory lung volume and become the ideal choice of patients with high carbonate type of respiratory failure. This paper reviews the application of HFNC therapy in hypercapnic respiratory failure in recent years.