Abstract: Although lung CT has an advantage in the diagnosis of pneumonia, but the clinical application in severe Coronavirus Disease 2019 (COVID-19) is faced with risks of cross infection and aggravation of illness condition. The purpose of this study is to investigate the characteristics of bedside ultrasound in the diagnosis and treatment of patients with severe COVID-19. Practice has proved that ultrasound is helpful to quickly screen the causes of respiratory failure in patients with COVID-19, and plays an important role in the process of diagnosis, treatment and rescue.