Whether multiple lung nodules are serious or not is closely related to the cause of the disease. If they are caused by infection, they are generally not serious and have a good prognosis after standardized treatment, while if they are caused by malignant tumors, they are relatively serious. Multiple pulmonary nodules refer to the presence of two or more round or irregular shaped lesions less than 3 cm in diameter in the lungs, which can be caused by a variety of reasons. The first thing to rule out is primary lung cancer. Diffuse nodules may be due to metastasis from an extrathoracic malignant tumor or active infection; primary lung cancer is less likely. Multiple pathogens, such as Mycobacterium tuberculosis or fungi can cause multiple lung nodules, the severity of the disease is related to the degree of infection, under the guidance and advice of the doctor timely anti-infection treatment, such as Mycobacterium tuberculosis caused by anti-tuberculosis treatment such as rifampicin, isoniazid and so on, the general prognosis is good. Multiple lung nodules caused by malignant tumors are relatively serious, whether primary or metastatic, it is necessary to improve the relevant examinations to clarify the condition, and comply with the doctor’s instructions to actively treat, otherwise it may affect the patient’s survival. The causes of multiple lung nodules are different, the severity will also be different, but all need to pay great attention to, need to go to the hospital in time to identify the cause, under the guidance of the doctor standardized treatment.