Radiotherapy utilizes X-ray, electron, proton, heavy ions and other radioactive materials to target and kill cancer, and represents one major cancer treatment strategy. More than half cancer patients receive radiotherapy. Therefore, how to improve the quality of radiotherapy becomes a subject of great economic and social significance. One important research field in medical physics is developing multimodality imaging techniques for image guided precision radiation therapy. The integrated image modalities provide comprehensive and complementary patient image information, such as anatomical, functional and molecular information of cancer and organs at risk, thus greatly improving the tumor targeting accuracy. They precisely localize the tumor before treatment, realtime monitor the tumor movement during treatment, and accurately assess the tumor response after treatment. This presentation will introduce the progress of image guided radiation therapy in clinical practice, and report the development of first triple-modality guided precision radiation therapy device in the University of Science and Technology of China.