Interstitial lung disease (ILD), also known as diffuse parenchymal lung disease (DPLD), pulmonary (interstitial) fibrosis or interstitial pneumonia. The so-called pulmonary fibrosis is the replacement of normal lung tissue with scar tissue, in the same way as scarring after a skin break. Scar formation thickens the interstitial lung mass, making it difficult for oxygen to be transferred from the alveoli to the blood. Low oxygenation of the blood leads to shortness of breath and decreased activity tolerance in patients with pulmonary fibrosis. Pulmonary fibrosis is a general term for a group of diseases. Although interstitial lung disease is not a new disease, it has not received much attention until recent years. As awareness and diagnostic techniques have improved, more and more patients are being diagnosed or suspected of having “interstitial lung disease”. Nevertheless, interstitial lung disease does not sound as familiar to the majority of patients as diseases such as asthma and pneumonia. Because many physicians are still unaware of the disease, there are few cases of misdiagnosis and misdiagnosis. The main clinical manifestations of interstitial lung disease are gradually worsening dyspnea and a gradual decrease in activity tolerance. The main clinical manifestations of interstitial lung disease are gradually worsening dyspnea and a gradual decrease in activity tolerance. The main tests for interstitial lung disease are high-resolution CT of the chest, pulmonary function tests, lung lavage and related etiological tests. The etiology of the disease is complex. Common causes include immune system diseases: e.g. rheumatoid arthritis, dermatomyositis, etc. There are also occupational factors: such as silicosis, coal lung, pigeon lung, etc. Drugs can also cause the disease, such as acetaminophen iodofurazone for heart disease. There are also many interstitial lung diseases of undefined etiology. Patients suspected of suffering from this disease should go to the respiratory department of the hospital as soon as possible, through the doctor’s detailed questioning and review of medical history, comprehensive physical examination, systematic examination and comprehensive analysis, clear diagnosis, give targeted standardized treatment, most patients can get complete remission or partial remission, life and work basically back to normal.