This study shows that CISD2 is down‐regulated in gastric cancer tissues and cells, and its effects on the inhibition of gastric cancer cell proliferation, migration, invasion, and the enhancement of chemotherapy sensitivity are mediated by the increase in 5‐FU‐induced apoptosis and the inhibition of autophagy through the AKT/mTOR pathway. This evidence concerns the gene CISD2 and gastric cancer.