Abstract: Objective: To assess the clinical observation of radioactive ¹²⁵I seeds interstitial brachytherapy for abdominal malignant tumors.Methods: Five patients with primary and metastatic liver cancer received ¹²⁵I seeds interstitial brachytherapy under CT.Four cases of pancreatic cancer and 1 case of metastatic liver cancer were treated with ¹²⁵I interstitial brachytherapy during laparotomy under outrasound guidance,and the follow-up lasted for 1-12 months.Results: The implanting was successfully in all the 10 cases.The pains were relieved obviously in 5 caes and no severe complications were observed.CT showed that the volume of the malignant tumors decreased to some extent during the 2-month follow-up,with an overall response rate of 90%.Conclusions: Radioactive seeds interstitial brachytherapy may relieve the symptoms of patients with abdominal malignant tumors and improve their life quality.