EUS-guided radioactive seeds implantation of iodine 125 combined with chemotherapy were used for the treatment of the retroperitoneal cancer which was non-operative, accessed to obtain the local remission in one case of the retroperitoneal metastatic adenocarcinoma. A 61-year-old Chinese woman presented to Changhai hospital with a one-week history of abdominal distention. MRI scan showed that there were many enlarged lymph nodes which were integrated near the hepatic portal and retroperitoneal, considered of lymphoma. The followings were laboratory tests (with normal range in parentheses): white cell count 8.92 × 109/L (4.0-10.0 × 109/L), hemoglobin 9.0 g/dl (10-15 g/dl), platelet count 239 × 109/L (100-300 × 109/L), GT 73 U/L (0-45 U/L), and the renal function was in the normal range. AFP and CA19-9 were normal, and the level of CEA in serum was 305ng/ml (0-10 ng/ml). The biopsy pathology was proved to be metastatic adenocarcinoma under the CT-guided puncture. Immunohistochemistry staining showed that it was metastatic adenocarcinoma, P53 (high level expression), Topo (drug fast gene middle level expression), proliferation of cell activity as moderate. Twice chemotherapy were performed on the patient and the interval was one month. The project of the chemotherapy was oxaliplatin200mg (d1), 5-Fluorouraci 750 mg (d1-d5) and Calcium Folinate 200 mg (d1-d5). MRI scan showed that the enlarged lymph nodes which were integrated near the hepatic portal and retroperitoneal were smaller than before. Since then, EUS-guided radioactive iodine125 seed implantation were performed twice. The seeds were implanted into the enlarged lymph nodes using 19T needle. 20 seeds were implanted at the first time, 12 seeds in the second, and the total number of the iodine-125 seeds was 32. The interval was 7 days. The implantation of radioactive seeds was secure for the patient, because there were no significant procedure-related complications which including acute pancreatitis and perforation. Laboratory test about hemogram and hemodiastase were both in the normal range, and liver function did not change significantly. Two months after the implantation of radioactive particles, two courses of the same chemotherapy were performed. Follow-up of 12 months, the patient's symptoms of abdominal distention was eliminated. Review on abdominal CT scan, enlarged lymph nodes which were integrated near the hepatic portal and retroperitoneal was completely disappeared.