Compared with cells transfected with si‐FXYD3, the expression of let‐7i and FXYD3 was enhanced in cells treated with si‐FXYD3 + EV‐mimic‐NC, the expression of KDM3A and DCLK1 was decreased, whereas the proliferation and invasion of lung cancer cells were inhibited, and the apoptosis was promoted. This evidence concerns the gene KDM3A and lung cancer.