Exosome is a kind of micro and nanometer level extracellular vesicles. Because it can directly participate in the transmission of information between cells and the transport of substances, exosome is considered to be an important carrier of biomarkers for intercellular communication, immunomodulation, disease diagnosis and prognosis. In addition, the nucleic acid and protein contained in exosome can affect significantly the physiological state of recipient cells. As an endogenous non-coding microRNA, miRNA is of great value in the diagnosis and treatment of diseases. There is a great deal of evidence that these molecules play a role in controlling and regulating the pathogenesis of lung diseases. This review article focuses on the biological characteristics and functional fields of exosome derived miRNA in recent years, and summarizes the regulation function and mechanism of exosomal miRNA in lung diseases, especially pulmonary fibrosis, which is a hot topic in biomedical research in recent years. Therefore, it can not only act as a new molecular biomarker for the diagnosis of pulmonary fibrosis, but also suggest a new therapy strategy for exosomal intervention of pulmonary fibrosis.