OBJECTIVE： To observe the efficacy and safety of sequential chemotherapy on the basis of 5-FU combined with three-dimensional conformal intensity modulated radiotherapy in the treatment of postoperative advanced gastric cancer. METHODS： 110 patients with advanced gastric cancer were randomly divided into control group （55 cases） and sequential group （55 cases）. Control group was given 400 mg/（m2·d） 5-FU injection by intravenous injection， then given 600 mg/m2 for continuous infusion 22 h， d1-2+50 mg/d Pirarubicin hydrochloride for injection， intravenous injection， d1+150 mg/d Oxaliplatin for injection， intravenous injection， d1，three-dimensional conformal intensity modulated radiotherapy was conducted for 2 weeks after the 4th chemotherapy，and the total dosage was DT40-45 Gy/1.8 Gy/24-25F. sequential group was additionally given three-dimensional conformal intensity modulated radiotherapy； 3-week was regarded as a treatment course， and it lasted 6 courses. The total survival rate and progression-free survival rate in 1，2 and 3 years， metastasis rate and incidence of adverse reactions in 2 groups were followed-up. RESULTS： The total survival rate and progression-free survival rate in 1， 2 and 3 years in sequential group were significantly higher than control group， lymphatic metastasis rate and distant metastasis rate in sequential group were significantly lower than control group， the differences were statistically significant （P＜0.05）. And there were no significant differences in the nausea， vomiting， hair loss and incidence of bone marrow suppression between 2 groups （P＞0.05）. CONCLUSIONS： Sequential chemotherapy on the basis of 5-FU combined with three-dimensional conformal intensity modulated radiotherapy can effectively prolong the survival time and reduce long-term metastasis rate of patients in the treatment of postoperative advanced gastric cancer， with similar safety.