China is one of the countries with the highest incidence of liver cancer, and surgical treatment is the preferred treatment method for liver cancer. However, due to the limitation of tumor stage, tumor site, liver reserve function and other factors, only 20% of patients with primary liver cancer have the chance of surgery. The 5-year survival rate of patients with small hepatocellular carcinoma is 40%-70% after surgical treatment. For hepatocellular carcinoma that cannot be surgically resected but is confined to the liver, the first consideration is interventional embolization chemotherapy (TACE). However, the 5-year survival rate of patients after TACE treatment is only 20%. The liver is a juxtacellular organ, and a part of the liver is damaged by high doses of radiation, and the uninjured normal liver can proliferate compensatively. Therefore, radiotherapy for hepatocellular carcinoma has a certain radiobiological basis. However, conventional radiotherapy in the past has the disadvantages of poor localization technique, large irradiation range, radiotherapy dose pattern cannot kill the tumor completely, and the local control rate and survival rate are low. In contrast, stereotactic radiotherapy (SBRT) uses imaging equipment to collect images of tumors and surrounding normal tissues, and with the cooperation of treatment planning system, uses the principle and technology of stereotactic orientation to precisely locate tumors in human body, concentrates narrow beams of radiation at the target site, and gives a large dose of radiation to cause focal destruction of tumors while minimizing damage to normal tissues to achieve the treatment purpose.