Objective:To evaluate the safety and short-term effect of CT-guided 125I radioactive seed implantation on regional lymph node metastasis after gastrectomy. Methods:Twenty-three patients with regional lymph node metastasis after gastrectomy received CT-guided 125I radioactive seed implantation from June, 2007 to July, 2011 in our hospital. The overall activity and amount of radioactive seeds were calculated by simulating source distribution of radioactive seed implantation plan system before operation. 125I seeds were implanted under the guidance of CT. Effective rate was evaluated according to RECIST criterion, 1, 2 and 3 years of survival rates were calculated by life table method, the effect of relative factors on survival was tested by univariate COX model, and the survival differences between subgroups were compared to draw survival curve by log-rank method. Additionally, systemic therapies were given to 20 patients based on lfuorouracil drugs. Results:No severe complications was observed in all study subjects with 14 complete remission (60.9%), 5 particle remission (21.7%) and 4 progressive diseases (17.4%), while 1, 2 and 3 years of survival rates as well as median survival time being (87±7)%,(47±11)%, (13±9)% and (22.1±5.1) months, respectively. Univariate COX analysis showed that the maximum diameter of tumor could badly inlfuence the prognosis (χ2=9.752, P=0.002), and the subgroups analysis relieved the signiifcant difference (χ2=5.828, P=0.016, log-rank test) with 3 cm being the cut-off value. Conclusion:CT-guided 125I radioactive seed implantation has high local control rate with small trauma and slight complications.