Objective To study the effect of curcumin (Cur) combined with monoamine oxidase A (MAOA) inhibitor clorgyline ( Clo) on lung cancer cell proliferation and its mechanism. Methods The effect of various concentrations of Cur and Clo on proliferation of the lung cancer cell line H460 was assessed by a CCK-8 assay. Western Blot was used to analyze the effect of Cur, Clo, and Cur combined with Clo on MAOA expression in H460 cells. The inhibitory effect of Cur, Clo, and Cur combined with Clo on H460 cell proliferation was further examined in a xenograft model in nude mice. Immunohistochemistry was used to assess the effect of Clo on Ki67 protein expression in tumor tissue of the xenograft model. TUNEL staining was used to detect apoptosis in various treatment groups of xenografted tumor tissue. Results Cur, Clo, and Cur combined with Clo inhibited H460 cell proliferation in a dose-dependent manner and H460 cell growth in the xenograft model (P< 0. 01), decreased the Ki67 expression, and increased apoptosis. Importantly, the combined treatment group showed more significant inhibitory effects (P< 0. 01). Conclusions Cur combined with Clo inhibits the proliferation of H460 lung cancer cells, which may be related to reducing expression of the cell proliferation protein Ki67 and increasing apoptosis.