Human lung is divided into left lung and right lung, right lung has three lobes, left lung has two lobes, right lung is divided into upper lobe, middle lobe and lower lobe, if the middle lobe of the lesion, it is called the middle lobe of the right lung lesion, also called middle lobe syndrome. Middle lobe syndrome is mostly caused by the following reasons: firstly, lung infection, bacteria, virus and unexplained infections, which can easily lead to the occurrence of pneumonia in the middle lobe of the right lung, and the clinical manifestations are cough, fever, and even blood in sputum. Chest CT and fiberoptic bronchoscopy can further clarify the cause of infection. Secondly, right lung middle lobe syndrome is prone to tuberculosis changes, which manifests as cough, blood in sputum, recurrent fever, and progressive emaciation. Fiberoptic bronchoscopy can be given to check for antacid bacilli in order to rule out the presence of tuberculosis as early as possible. Thirdly, tumorous lesions in the middle lobe of the right lung, the tumor grows in the lumen and gradually blocks the lumen of the bronchus, forming obstructive pneumonia and pulmonary atelectasis, which is also prone to cough, chest tightness, chest pain, blood in sputum and cancerous fever, and it is necessary to give fibreoptic bronchoscopic cytology examination to clarify whether it is a tumor disease as early as possible. Thus, right lung middle lobe lesions, also known as middle lobe syndrome, are mainly suggestive of inflammatory, tuberculous, and neoplastic diseases in all three areas.