We aimed to investigate the mechanism and effects of autophagy on cisplatin (DDP)-induced apoptosis inhuman gastric cancer cell line SGC7901. After SGC7901 cells were treated with DDP and/or chloroquine, cellproliferation was measured using MTT assay; cell apoptosis was determined by flow cytometry; autophagy andapotosis-related proteins expression were detected by Western blot; and quantitative analysis of autophagy aftermonodansylcadaverine (MDC) staining was performed using fluorescence microscopy. We found after treatmentwith 5 mg/L DDP for 24 h, the rates of cell apoptosis were (21.07±2.12)%. Autophagy, characterized by an increasein the number of autophagic vesicles and the level of LC3-II protein was observed in cells treated with DDP.After inhibition of autophagy by chloroquine, the rates of cell apoptosis were increased to (30.16±3.54)%, andthe level of Caspase-3 and P53 protein were increased, and Bcl-2 protein was decreased. Therefore, autophagyprotects human gastric cancer cell line SGC7901 against DDP-induced apoptosis, inhibition of autophagy canpromote apoptosis, and combination therapy with DDP and chloroquine may be a promising therapeutic strategyfor gastric cancer.