Our study assessed the effect of miR-21 mediating Nerve Cell Adhesion Molecule (NCAM) and Glial Cell-line Derived Neurotrophic Factor (GDNF) on the proliferation and apoptosis of lung cancer cells. Lung cancer cell-line H460 cells were grouped as Lung cancer group (LC group) (normal cultivation); Mimic group (SI group) which was transfected with 120 nmol/L miR-21 mimics and liposomes; Inhibitor group (IN group) (transfection of miR-21 inhibitor and liposomes) followed by analysis of cell apoptosis by Hoechst 33258 staining, GDNF level by immunohistochemistry, miR-21 level by qRT-PCR, cell proliferation by CCK-8 and NCAM level by western blot. miR-21 content was significantly increased in SI group, indicating a successful transfection. The nucleus shrinkage rate in IN group and LC group was higher than SI group (P <0.05) and IN group had highest number of apoptotic cells, lowest cell proliferation and NCAM level among three groups (P <0.05). SI group showed significantly higher positive GDNF staining than IN and LC group (both P <0.05). miR-21 promotes H460 cell proliferation and inhibits cell apoptosis by upregulating NCAM and GDNF.