Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in China.When HCC is diagnosed, most patients have been at the middle or advanced stage and have lost the chance of radical resection.In recent years, the roles of targeted therapy, immunotherapy, and radiotherapy have become increasingly prominent in the treatment of unresectable HCC.Although HCC is sensitive to radiation, the clinical value of radiotherapy is often underestimated due to the low tolerance of liver to radiation.With the development of radiotherapy technology, radiotherapy has been widely used in unresectable HCC.Patients can gain more survival benefits whether treated with radiotherapy alone or in combination with other treatments.This review focuses on the application and progress of radiotherapy and its combination therapy in unresectable HCC.