Abstract: Objective To investigate the mechanism of microRNA-149 （miR-149） in regulating cell proliferation and apoptosis in non-small cell lung cancer （NSCLC）. Methods MiR-149 mimics and its control vectors were transfected into A549 cells by Lipofectamine liposome and assigned into miR-149 transfection group and miR-149 control group. The non-transfected A549 cells were served as controls （non-transfected group）. The miR-149 levels of three groups were detected by real-time quantitative PCR （QPCR） in order to evaluate the transfection efficiency. The MTT and Annexin V-FITC／PI flow cytometry were used to compare the proliferation and apoptosis among miR-149 transfection group， miR-149 control group and non-transfected group. QPCR was used to detect the expression of FOXM1 gene in each group， and the expression of FOXM1 protein was detected by Western blotting. Double luciferase reporter assay was applied to verify the targeting relationship between miR-149 and FOXM1. Results The QPCR detection showed that the relative expression of miR-149 in the miR-149 transfection group was 2.493±0.380， at 48 h after transfection， higher than 1.077±0.321 in the non-transfected group and 1.283±0.273 in the miR-149 control group（P＜0.05）. The proliferation inhibition rates of miR-149 transfection group were （16.51±2.49）％， （22.90±3.65）％ and （3143±5.27）％ at 24， 48 and 72 h after transfection， higher than other two group （P＜0.05）. The apoptotic rate of miR-149 transfection group was （29.17± 4.48）％ at 48 h after transfection， higher than （5.34±1.72）％ of the nontransfected group and （7.62±1.59）％ of miR-149 control group （P＜0.05）. The mRNA and protein levels of FOXM1 in miR-149 transfection group were 0.624±0.102 and 0.349 ±0.065 at 48 h after transfection， lower than 0.976±0.076 and 0.654±0.074 in non-transfected group and 0.920±0.117 and 0.718±0.077 in miR-149 control group （P＜0.05）. Double luciferase reporter gene test showed that miR-149 could significantly inhibit the luciferase activity of wild type FOXM1-3 UTR， but had no effect on the luciferase activity of mutant plasmid transfected cells. Conclusion miR-149 may regulate the proliferation and apoptosis of lung cancer A549 cells by targeting FOXM1， and can be used as an effective target for the molecular therapy of NSCLC.