Objective:To explore the expression of microRNA-224 (miR-224)in non-small cell lung cancer (NSCLC)and its effect proliferation and apoptosis of NSCLC cell. Methods:Real-time quantitative PCR(qPCR)was used to detect and compare the expression of miR-224 in 20 pairs of NSCLC,adjacent normal tissue,NSCLC cell line A549 and normal epithelium cell line 16HBE. The expression of miR-224 in A549 cell was down-regulated by anti-miR-224 transient transfection,and the effect was identified by qPCR. The influence of miR-224 on A549 cell proliferation was detected by MTT assay and colony formation assay. Flow cytometry was used to test cell cycle and apoptosis. The expression of Bim was tested by anti-miR-224 transient transfection,and the effect was identified by qPCR and western blot. Results:Compared with adjacent normal tissues,miR-224 were significantly up-regulated in NSCLC tissue and cell.(P < 0.05). Down-regulating miR-224 can inhabits proliferation and accelerates apoptpsis as well as increasing the expression of Bim. Conclusion:The expression of miR-224 is up-regulated in NSCLC. MiR-224 can promotes proliferation and inhabits apoptosis by down-regulating Bim.