Abstract: Objective: To investigate the effect of CT- guided ¹²⁵I radioactive seed implantation on primary hepatic carcinoma and extrahepatic metastases. Methods: Data from 31 patients with 65 total lesions (mean diameter of 3.5 cm) were collected. There were 20 lesions in the liver, 25 metastatic lesions in the lung, 15 lymph node metastases and 5 osseous metastases. The diagnosis of each of the 31 cases was verified by CT, MRI or biopsy.¹²⁵I seeds of 0.8 mCi were implanted into the 65 lesions at an interval of 0.5- 1.0cm according to treatment plan system (TPS). Matching perimeter dosage (MPD) was 100- 150 Gy. Results: After 2 months, CT examination showed complete remission (CR) in 4 patients,partial remission(PR) in 18 patients, no change(NC) in 3 patients, and progressive disease(PD) in 6 patients. The response rate was 71.1%(22/31) and the rate of pain amelioration was 72.7%(8/11). Among the 65 lesions, we observed CR in 18, PR in 35, NC in 8, and PD in 4. The local control rate was 81.5%(53/65). Two patients died of metastasis and 3 patients died of liver failure. Two months after the operation, 8 seeds had migrated into the liver, and 5 seeds had migrated into the lung. Pneumothorax was seen in 2 cases, and the lung was compressed to less than 30% of its normal size. WBC count decreased slightly in 2 cases after the operation, but the count was still over 3.0× 109/L. Complications like radiation pneumonia, hemorrhoea, biliary fistula and pancreatic fistula were not observed. Conclu-sion: CT- guided ¹²⁵I radioactive seed implantation has good clinical effects with minimal damage and few complications for treating primary hepatic carcinoma and metastatic hepatic carcinoma.