Objective To study the efficacy and adverse reactions of ftorafur with synchronous radiation therapy on brain metastasis from gastrointestinal tract. Methods Forty-three patients were divided into observation group and control group. The control group received 30 Gy whole brain irradiation and amount local suppltmentary to 50 Gy, before more than half an hour. Observation group received intravenous infusion of ftorafur 1.0 g. Through follow-up and periodic MRI examination to observe average survival time，the recurrence rates of brain metastasis focus, the primary recurrence rates,uncontrolled and / or brain metastasis rates,half and one year survival rates and the incidence of adverse reactions. Results In observation group and control group, the median survival time were 13 months and 9 months (χ²=10.282，P=0.001);53.4% and 27.3% for the one-year survival rates(χ²=6.85，P=0.009); 9.5% and 45.5% for the recurrence rates of brain metastasis (χ²=5.22, P <0.05); 85.7% and 40.9% for myelosuppression (χ²=7.41, P<0.05); 61.9% and 10% for gastrointestinal reactions(χ²=10.97, P<0.05); the differences were significant. Conclusion Ftorafur with synchronous radiation therapy for brain metastasis from gastrointestinal tract improves the one year survival rate and reduces the incidence of brain metastases. But the bone marrow suppression incidence and gastrointestinal reaction rates are increased; the gastrointestinal reaction can be alleviated by symptomatic treatment.