Objective: To investigate the treatment efficacy of radiofrequency ablation (RFA) of hepatic tumors and the relevant complications. Methods: A total of 343 patients with 778 hepatic tumors underwent ultrasound-guided RFA (582 procedures). There were 212 cases of hepatic cellular carcinoma (HCC) with 448 tumors, and the average largest diameter was 4.0 cm.Of all the patients, 63 (29.7%) were in the stage of Ⅰ-Ⅱ(UICC Systems) and 149 (70.3%) in stage of Ⅲ-Ⅳ(including 43 patients with tumor recurrence after surgical resection). There were 131 cases of metastatic liver carcinoma (MLC), with 330 metastases in the liver, the average diameter was 3.9 cm, and the liver metastases of 91 patients (69.5%) came from gastrointestinal tract. The patients were treated using the relatively standard protocol. Crucial attention must be paid to monitoring the abnormal changes in ultrasound images as well as the vital signs of the patients to find the possible hemorrhage and peripheral structure injury in time. The tumors were considered ablated successfully if no viability was found on enhanced CT within 24 hours or 1 month after RFA. The patients were followed up for 2 -62 months.Results: The ablation success rate for HCC was 95.5% (428/448 tumors), and the rate for MLC was 96.4% (318/330 tumors). The local tumor recurrence rates for HCC and MLC were 8.5 % (38/448 tumors) and 11.8 % (39/330 tumors), respectively. A total of 138 patients (40.2%) underwent repeated ablations for 2-11 times because of tumor recurrence or metastasis. The first,second and third years survival rates were 87.7% , 67.4% and 56.8% for HCC patients, 81.6%, 50.8% and 27.2% for MLC patients,respectively. The survival rate from 63 early-stage HCC patients were 92.9%,82.8% and 74.5%, respectively. The major complication rate in this study was 2.4 % (14 of 582 procedures).The complications which consisted of mechanical and thermal injuries usually occurred during or shortly after the RFA treatment. There were 5 hemorrhages, 1 colon perforation, 5 injuries of adjacent structures, 2 bile leakages and 1 skin burn. Conclusion: RFA, as a minimally invasive local treatment, has become an effective and relatively safety alternative for the patients of hepatic tumors, even of advanced live tumor, tumor recurrence, liver metastases which are unresectable or difficult to treat with traditional therapies. Knowledge about possible complications and their control may increase the treatment efficacy and help to promote the use of RFA technique.