Objective To explore the research status and development tendency of relation between indoleamine 2，3-dioxygenase （IDO） and immune escape of gastric cancer. Methods The related literatures about IDO， immune escape of gastric cancer， and their the relationship at domestic and international in recent ten years were collected and reviewed. Results Gastric cancers induced that dendritic cells expressed IDO by the CD4＋ CD8＋ regulatory T cells， which made the microenviroment tryptophan starvation， thus inhibited T cell proliferation. While tryptophan metabolites existed T cell cytotoxicity that inhibited T cell proliferation. IDO-specific inhibitor 1-MT combinated with chemotherapy drugs in the treatment for gastric cancer was a synergistic effect. Conclusions IDO as an immune modulating enzymes may play a key role in the process of immune tolerance that induced by gastric body. IDO may become a new target for inhibition of gastric malignancy formation and enhance the effectiveness of tumor immune treatment.