Radiofrequency ablation, as a treatment method emerging in the past 20 years or so, has become an alternative treatment method to surgery for certain types of liver cancer, or an important adjuvant treatment method to liver resection surgery, with its characteristics of safety, minimally invasive, wide indications, few complications and repeatable application. Treatment principle: Using special treatment needle, the high frequency electromagnetic wave generated by RF instrument is introduced into local tissues, which excites ions in tissue cells and generates high temperature of about 100℃-110℃, causing coagulative necrosis of tumor tissues. There are three treatment routes: one is direct percutaneous penetration of liver tumor by ultrasound guidance or CT guidance; the other is penetration of liver tumor under laparoscopy; the third is direct use in traditional open surgery. Indications for treatment: 1. single tumor with maximum diameter ≤ 5 cm; or number of tumors ≤ 3 with maximum diameter ≤ 3 cm; 2. no choroidal cancer embolism, no adjacent organ invasion; 3. liver function grade Child-Pugh A or B, or the standard is achieved by medical treatment; 4. single tumor with diameter > 5 cm or multiple tumors with maximum diameter > 3 cm that cannot be surgically resected, local ablation can be used as part of palliative treatment or combined treatment. After treatment, liver function, serum tumor markers and B-ultrasound should be reviewed regularly, and enhanced CT or MRI should be reviewed one month after treatment. The standardized method to assess local efficacy is about 1 month after ablation. At 1 month after treatment, the liver was reviewed with three CT/MRI scans, or ultrasonography to evaluate the ablation efficacy. The efficacy can be classified as follows: 1. complete response (CR) The tumor is hypointense (hyper-echoic on ultrasound) in the area where the tumor is located, and no enhancement is seen in the arterial phase. 2. incomplete response (ICR) The follow-up of ultrasonography, localized enhancement in the arterial phase within the tumor lesion, suggests the presence of tumor residue. For those who have tumor residue after treatment, ablation therapy can be performed again; if there is still tumor residue after 2 ablations, it is considered as ablation therapy failure, and ablation therapy should be abandoned and other therapies should be used instead.