Exosomes, as a nano‑scale carrier, are one of the most important types of extracellular vesicles. MicroRNA (miRNA) are a class of non‑coding RNAs with endogenous regulatory functions found in eukaryotic organisms. Exosome‑derived miRNA has broad application prospects in pulmonary diseases. This article reviews that exocrine miRNA can regulate lung diseases through a variety of substances/signal transduction, such as acute lung injury, lung cancer, chronic obstructive pulmonary disease, and COVID‑19. This review focuses on the research advances of exosome miRNA in the diagnosis and treatment of the above‑mentioned lung diseases. With the deepening of the research on exosome miRNA in lung diseases, more new ideas and methods may be provided for the diagnosis and treatment of lung diseases in the future.