Book excerpt: Respiratory support is a series of significant techniques used widely in clinical which saves a great number of patients with impaired pulmonary function and respiratory failure caused by pneumonia, sepsis, trauma, and acute exacerbation of chronic obstructive pulmonary disease, especially in recent years of Covid-19. It could improve oxygenation, reduce respiratory rate, and maintain normal ventilation. These techniques include oxygen therapy, high-flow nasal cannula, noninvasive ventilation, mechanical ventilation, and extracorporeal membrane oxygenation et al. Respiratory support has been improved increasingly these 20 years. Summarizing experience from past cases and keeping up with the latest technology is crucial to improve patient management and prognosis.