Objective：To validate whether interferon regulation factor 3（IRF3）is regulated by long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1（MALAT1）. Methods：Luciferase report plasmid pGL3-56 inserted with IRF3 promoter and MALAT1 knockdown siRNAs（negative control，siMALAT1-1 and siMALAT1-2） were co-transfected to A549 cells，then relative luciferase activities were determined. MALAT1 knockdown siRNAs were transfected to A549 cells，then IRF3 mRNA and protein levels were detected by qPCR and Western blotting respectively. Results：Relative luciferase activities of the siMALAT1-1 and the siMALAT1-2 groups were lower than that of the siNC group respectively，which were statistically significant（P < 0.05）. Relative MALAT1 RNA levels of the siMALAT1-1 and the siMALAT1-2 groups were lower than that of the siNC group respectively，which were statistically significant（P < 0.05）；Relative IRF3 mRNA levels of the siMALAT1-1 and the siMALAT1-2 groups were lower than that of the siNC group respectively，which were statistically significant（P < 0.05）. Relative IRF3 protein levels of the siMALAT1-1 and the siMALAT1-2 groups were lower than that of the siNC group respectively，which were statistically significant（P < 0.05）. Conclusion：IRF3 is a target of MALAT1 and MALAT1 regulates the expression of IRF3 by targeting IRF3 promoter.