According to the technical characteristics of radiofrequency ablation, the range of radiofrequency ablation should exceed 1cm of tumor edge to achieve complete tumor necrosis. The range of RF ablation with one electrode needle is 5cm in diameter. Liver tumors below 3cm can be completely covered by RF ablation after one electrode insertion. 67% of liver tumors below 3cm are reported to be completely necrotic after RF ablation, which has better therapeutic effect. However, when the liver tumor is 3-4cm, the electrode needle needs to be adjusted for at least 6 times of RF ablation, and the residual tumor rate and recurrence rate are significantly higher. Therefore, the most suitable patients should have liver tumor less than 3cm and the number of liver tumors should be less than 3. If the size of liver tumor is more than 5cm, it is better to consider surgical resection first. In addition, patients with severe cirrhosis or poor health condition who cannot tolerate surgical liver resection can also be considered for liver tumor radiofrequency treatment. There are roughly three methods of radiofrequency treatment, one is to put electrode needles into liver tumor directly from the surface of liver through ultrasound guidance or CT guidance; the second is to put electrode needles into liver tumor through television laparoscopy under direct vision during surgery, and also under the guidance of laparoscopic ultrasound; the third is to put electrode needles directly into liver tumor during surgery. Thirdly, electrode needles can be placed directly during surgery, in which case the tumor cannot be removed or the cirrhosis is too severe to be removed and intraoperative radiofrequency treatment can be done.