Abstract: Lung cancer has the highest morbidity and mortality rate among malignant tumors. Early diagnosis and effective treatment are the keys to improving the survival of lung cancer patients. A type of endogenous, highly conserved, non-coding small molecule RNA (i.e., miRNA) was found to play an important role in the occurrence and development of this disease. Research on this molecular marker miRNA for the diagnosis, treatment and prognosis of lung cancer has rapidly progressed. This paper reviews the research work on miRNA as a molecular marker in the early diagnosis, treatment efficacy, and prognosis of lung cancer and explores some questions related to this disease.