Coughing rust-colored sputum is mainly caused by Streptococcus pneumoniae, an acute inflammatory disease that involves most or all of the large lobes of the lung and is dominated by diffuse fibrinous exudation in the alveoli. In addition to Streptococcus pneumoniae, S. pneumoniae, Staphylococcus aureus, Streptococcus haemolyticus, and Haemophilus influenzae can also cause lobar pneumonia. Attention should be paid to the differential diagnosis in clinical practice. Specifically as follows. 1, mucopurulent sputum: most likely suffering from acute and chronic bronchitis secondary to infection, bronchial dilatation, lung abscess and other diseases. 2.Yellow mucous sputum: It may be caused by lung infection due to the presence of a large number of pus cells. 3.Green sputum: may suffer from diseases such as pulmonary sputum dissipation period caused by Pseudomonas aeruginosa, lung cancer, and bronchial dilatation. 4.Brown sputum: It may be caused by chronic passive stasis caused by pulmonary infarction and heart disease. 5, rust-colored sputum: may suffer from lobar pneumonia. The different color of sputum is precisely a reminder to focus on specific health in a targeted manner.