The change from yellow sputum to white sputum in pneumonia is considered to be a symptom of gradual improvement of pneumonia. During pneumonia, if yellow sputum appears, it is more likely to consider bacterial infection. But also need to improve the blood routine and sputum culture, drug sensitivity test, to clarify which germ infection. In case of yellow sputum, it is recommended to use antibiotics or antiviral drugs for treatment according to the results of sputum culture and blood routine, and other oral or intravenous drugs if necessary. If the sputum becomes viscous or changes from yellow to white sputum, the symptoms are gradually improving, but it is necessary to continue the treatment with medication. After the course of treatment, the relevant indexes should be reviewed, and the chest CT should also be reviewed.