Abstract: Objective To study the effects of emodin on cell proliferation, apoptosis and secretion of vascular endothelial growth factor-A (VEGF) and tumor necrosis factor-α (TNF-α) of human lung adenocarcinoma A549 cells in vitro. Methods MTT assay was applied to determine the cell proliferation of A549 cells after treated with emodin at different concentrations (5, 10, 20, 40, 80 μmol/L) for different time durations (12, 24, 48 and 72 h). The apoptotic A549 cells were double-color stained with annexin V-FITC and propidium iodide (PI) and then measured with flow cytometry (FCM); The apoptotic A549 cells were also stained by Hoechst 33258 and examined under fluorescence microscope. The culture medium supernatants of A549 cells treated by emodin were collected and concentrations of VEGF and TNF-α were analyzed using enzyme-linked immunosorbent assay (ELISA). Results Emodin significantly inhibited cell proliferation and promoted apoptotic rate of human lung adenocarcinoma A549 cells, and reduced VEGF expression and secretion but enhanced TNF-α expression and secretion in concentration- and time-dependent manners. Conclusion Emodin has potentials of anti-proliferation, pro-apoptosis and anti-angiogenesis in human lung adenocarcinoma A549 cells, so that emodin could be developed as a new antitumor agent for non-small cell lung cancer (NSCLC) therapy.