Multiple small mediastinal lymph nodes in the lungs are usually the result of the presence of more lymph nodes in the chest, usually due to pneumonia, malignant tumors of the lungs, lymphoma and so on. It is recommended that patients go to the hospital for diagnosis and treatment. 1. Pneumonia: Decrease in body resistance will cause bacterial infection leading to pneumonia, and the inflammatory reaction will cause small lymph nodes. Pneumonia will lead to coughing, coughing up phlegm, fever, chest pain and other symptoms. It can be treated with antibiotics. 2. Malignant tumor of lungs: malignant tumor cells will transfer to mediastinal lymph nodes through lymphatic vessels in lungs, which will cause enlargement of mediastinal lymph nodes, called mediastinal lymph node metastasis. Lung malignant tumor should be operated as early as possible if it can be operated, and patients who cannot be operated and postoperative patients should be treated with radiotherapy, immunotherapy, targeted therapy and so on. 3. Lymphoma: lymphoma invades the lungs and causes multiple nodules in both lungs and mediastinum, which requires the application of chemotherapeutic drugs and hormonal drugs, commonly used drugs include vincristine and prednisone. It is recommended to go to hospital for timely diagnosis and treatment under doctor’s guidance when patients have multiple small lymph nodes in the mediastinum of lungs.