Interstitial lung disease (ILD) are a general term for a group of clinically heterogeneous diseases characterized by inflammation and fibrosis of the lung interstitium. Due to the overlap and intersection of the clinical, radiological and pathological features of ILD, its diagnosis and treatment still face many challenges. In terms of diagnosis, the early diagnosis rate of ILD is low. It is difficult to confirm the disease type based on changes in imaging, specimens of bronchoalveolar lavage fluid or even lung tissue specimens. In terms of treatment, except for some secondary ILD with known etiology, most ILD can only delay the progression of disease with immunosuppressive and antifibrotic treatment. There is currently a lack of specific antifibrotic drugs. With the application of related pathogenesis research and new diagnostic and therapeutic techniques, it is expected that the difficulties in the diagnosis and treatment of ILD will be gradually overcome.