〔Abstract〕 Objective To investigate whether all-trans-retinoic acid(ATRA) treatment affects the survival ofgastric cancer patients after surgery, and to analyze whether ATRA affects the proliferation, migration, invasion and apoptosis of gastric cancer cells by regulating epithelial-mesenchymal transition(EMT). Methods A total of 198 patients with gastric cancer after surgery were selected and divided into control group and ATRA group, and the difference in survival time between the two groups was compared. MGC-803 gastric cancer cells were culturedin vitroand divided into control group and ATRA group. The proliferation ability was detected by CCK-8 experiment, the migration ability was detected by cell scratch experiment, the invasion ability was detected by Transwell experiment, and the apoptosis was detected by flow cytometry. The expressions of EMT-related genes(E-cadherin, N-cadherin and Vimentin) were detected by Western blot, RT-qPCR and immunofluorescence. Results ATRA could prolong the survival time of patients after gastric cancer surgery. After ATRA treatment, the proliferation, migration and invasion abilities of gastric cancer cells decreased, and the apoptosis of gastric cancer cells was promoted at the same time. Western blot, RT-qPCR and immunofluorescence results showed that ATRA down-regulated the expression levels of N-cadherin and Vimentin and up-regulated the expression level of E-cadherin in gastric cancer cells. Conclusion ATRA can prolong the survival time of gastric cancer patients after surgery, promote the apoptosis of gastric cancer cells, and inhibit the proliferation, migration and invasion of gastric cancer cells by regulating EMT.