Sputum culture refers to the selection of sputum for culture of bacteria, fungi and other pathogens. The first sputum in the early morning is generally more informative but not mandatory, and deep sputum from other times of the day can also be selected. Sputum culture is mainly to culture sputum for pathogens such as bacteria, fungi and tuberculosis, as well as to perform drug sensitivity tests. It is mainly used to consider patients with respiratory tract infections, especially those with lung infections, and can guide the choice of antibiotics for treatment. The first sputum in the early morning after gargling with light saline is usually required, but sputum from other times of the day can also be chosen, but deep sputum is required to rule out the possibility of sputum specimens being contaminated by settled bacteria in the oropharynx. In addition, patients undergoing diagnosis need to be assisted with other tests to be performed. The results of sputum culture can be directly related to the treatment method, so patients should follow the doctor’s instructions, and sputum should also be sent for examination as soon as possible after sputum is retained to avoid contamination or death of certain bacteria.