Abstract: Long non- coding RNAs (lncRNAs) have gradually become a research hotspot in recent years. The abnormal expression of some lncRNAs has been proven to promote tumorigenesis and progression. Among the lncRNAs, metastasis-associated lung adenocar -cinoma transcript 1 (MALAT- 1) has attracted considerable attention in various tumor studies, particularly lung cancer. Therefore, the mechanism in which MALAT- 1 regulates the cellular activities of tumors should be analyzed. This review mainly discusses the molecu -lar structure, biological function, and role of MALAT- 1 in regulating cell proliferation, tumor metastasis, cell cycle, apoptosis, and so on. Furthermore, the role of MALAT- 1 in epigenetic regulation is appropriately illustrated to provide a novel perspective in literature on the prevention and treatment of tumors.