Objective To compare the therapeutic effects and adverse reaction of concurrent chemoradiotherapy with pure chemotherapy for local progressive gastric cancer following D2 lymph node dissection. Methods Seventy-nine patients with progressive gastric cancer who underwent R0 gastric resection and D2 lymph node dissection were randomly divided into two groups. After radical gastrectomy, the experimental group (n=40) received radiotherapy concurrent with capecitabine chemotherapy, and then followed by 4 cycles of XELOX chemotherapy; however, the control group (n=39) only received 6 cycles of XELOX chemotherapy. The local recurrence rates, 3-year disease-free survival rates, 3-year overall survival rates and adverse reactions were evaluated after the treatment. Results The local recurrence rate in the experimental group was significantly lower than that of the control group (40.0%[16/40] vs 64.1% [25/39],P=0.032). The 3-year disease-free survival rates and 3-year overall survival rates of the experimental group were higher than those in the control group, but with no significant difference (P>0.05). The 3-year overall survival rate of patients with positive lymph node was significantly higher in the experimental group than in the control group (45.2% [14/31] vs 18.5% [5/27], P=0.049), with their median disease-free survival (mDFS) periods being 26 months and 19 months, respectively (P=0.024). The incidences of hematological and gastrointestinal toxicities in the experimental group were higher than those in the control group. Conclusion Concurrent chemoradiotherapy and chemotherapy can greatly reduce local recurrence after curative resection and D2 lymph node dissection in gastric cancer patients. In patients with lymph node-positive gastric cancer, postoperative concurrent chemoradiotherapy may improve their survival. The main adverse reactions of the concurrent treatment are hematological and gastrointestinal toxicities.