In order to explore the roles of miRNA(s) involved influenza A virus life cycle, we compared the miRNA profiles of HEK293 and HeLa cell lines, since influenza A virus can replicate efficiently in HEK293cells but poorly in HeLa. We analyzed the differentially expressed miRNAs andidentifiedfive of miRNAs including miR-33a which can disturb influenzaA virus replication significantly. By taking the approach of TargetScan analysis, we found that ARCN1 could be a potential target of miR-33a. To confirm whether miR-33a can truly target ARCN1, we generated luciferase reporterfor ARCN1 3´UTR and performed luciferase assay. The data indicated that miR-33a can suppress the luciferase activityof reporterfor ARCN1 3´UTRbut not reporter in which the predicted miR-33a targeting sites on ARCN1 3´UTR were mutated. We performed the immunoblotting analysis to confirm that miR-33a can downregulate the protein level of ARCN1. Consistently, the level of ARCN1 protein in HeLa cells was significantly lower than that in 293T cells. We also demonstrated that ectopic expression of ARCN1 can partially rescue the inhibitory effect of miR-33a onviralreplication.Furthermore, we demonstrated that miR-33a can impede the viral replication at the stage of viral internalization which is similar as the pattern as knockdown of ARCN1indicating that miR-33a inhibits influenza virus infection through suppressing ARCN1 expression. In addition, we found that miR-33a can also weaken the vRNP activity in an ARCN1 independent manner. In conclusion, we revealed that miR-33a is a novel inhibitory factor for influenza A viral replication.