Abstract: Malignant tumor is one of the leading causes of human mortality, with more than half of cancer patients requiring radiotherapy during treatment in developed country especially in USA. Over the past decades, radiotherapy has evolved around the principle of “enhancing efficacy while reducing toxicity” continuously integrating with surgery, chemotherapy, and immunotherapy, greatly improving treatment outcomes and accessibility. In 21st century, advancements in radiotherapy have been achieved through the adoption of more advanced dose delivery techniques, incorporation of real-time adaptive planning, introduction of artificial intelligence, and new types of radiation particles. This article reviews the technological advancements in radiotherapy over recent decades, showcasing typical cases of high dose rate radiotherapy research on accelerator platforms, summarizing emerging research hotspots in radiotherapy, and providing prospects for the future direction of the field.