Exosomes are nano-sized lipid bilayer vesicles that are fused by the cell membrane and multi-vesicles and released into the extracellular space by exocytosis. Exosomes play an important role in intercel-lular communication. MicroRNAs (miRNAs) are a class of endogenous non-coding RNAs consisting of 18~24 nucleotides. miRNAs play an important role in the regulation of post-transcriptional gene expression. Pul-monary fibrosis is an irreversible and progressive chronic lung disease. Many studies have shown that abnor-mal expression of exosomal miRNAs is closely related to the development of pulmonary fibrosis. This review focuses on the biological characteristics of exosomes and miRNAs, and discusses the important roles of exo-somal miRNAs in pulmonary fibrosis and their potential as a novel biomarker in this disease.