Starting from the initial empirical radiotherapy model, tumor radiotherapy has undergone several generations of hard work, research and innovative development, and so far there has been a drastic and huge change, with tremendous progress in both radiotherapy model and efficacy. Nowadays, evidence-based medical model has become the basis of radiotherapy, and with the application of cloud computing technology in the medical field, various guidelines formed by many evidence-based medical evidence can allow us to quickly retrieve a large amount of useful medical information in a short period of time. However, the evidence-based medical model with a large amount of statistical data is mainly based on the treatment data information of the whole patient group, it is a treatment model for the whole patient group, and its grouped information used to guide the treatment of individual patients is defective. Therefore, more and more medical experts believe that “individualized radiotherapy” is the main development direction and the ultimate goal of tumor radiotherapy in the future; at present, the most ideal mode of tumor radiotherapy is the “tailor-made” treatment based on the information of individual clinical, pathological, molecular and genetic level parameters and under the guidance of “individualized radiotherapy”. The most ideal model of tumor radiotherapy is “tailor-made” treatment based on the collection of information and guidance of individual clinical, pathological, molecular and genetic parameters. Individualized radiotherapy needs to identify the subgroups of patients who are effective for radiotherapy and define the optimal dose of individualized radiotherapy for patients, and outline the sub-target areas of different biology. There are two ways to classify individualized radiotherapy, namely patient population and image-guided modality. Patient group classification means that individualized radiotherapy can be divided into individualized radiotherapy between patient groups and individualized radiotherapy between individual patients. Individualized radiotherapy between groups refers to the use of different target area outlining, irradiation dose and segmentation patterns for different groups because of the different clinical, pathological and biological characteristics of different groups; individualized radiotherapy between individuals refers to the timely adjustment of radiotherapy target area and revision of radiotherapy target area for individual patients because of the changes in individual biological characteristics over time such as changes in the tumor itself, shrinkage of the tumor, and changes in the tumor’s oxygen depletion, proliferation, and metabolism, and the timely adjustment of radiotherapy target area. Timely adjustment of radiotherapy target area, revised dose or irradiation pattern. The classification of image-guided radiotherapy can be divided into anatomical image-guided individualized radiotherapy and biological image-guided individualized radiotherapy. Anatomical image-guided individualized radiotherapy is also known as physical individualized radiotherapy, which takes into account the changes in the target area due to respiration and physiological movements, as well as the changes in the patient’s body weight and the shrinkage of the tumor in the course of radiotherapy. Functional image-guided individualized radiotherapy, also known as bio-individualized radiotherapy, pursues the inhomogeneity of the target area due to tumor metabolism, oxygen depletion, proliferation, etc., and delivers different doses to the target area or sub-target areas with different biological characteristics, as well as applies the patient’s individual biological characteristics for monitoring and predicting the efficacy of the treatment. The cornerstone of individualized radiotherapy is modern molecular imaging medicine and molecular pathology, and the main purpose of applying molecular imaging and molecular pathology is the outline of biological target area and the precise illumination of biological dose. Theoretically, it is unreasonable to give uniform dose irradiation to inhomogeneous target areas in anatomical image-guided radiotherapy; while the use of functional image-guided radiotherapy for sub-target areas with different biological characteristics can be achieved by adopting different dose gradients to achieve “dose sculpture” irradiation which is more in line with the actual condition of the tumor. Therefore, molecular image-guided individualized radiotherapy is the direction of future development of tumor radiotherapy, which requires individualized target area outlining and individualized dose irradiation, and achieves maximum improvement of therapeutic efficacy and reduction of damage. “Individualized radiotherapy” is based on the comprehensive treatment model of evidence-based medicine, based on the morphology of high-resolution images provided by medical anatomical images, taking into account the genetic mutations of individual tumors, the radiosensitivity of different sub-target areas, and the biological characteristics of the internal metabolism, oxygen depletion, proliferation, apoptosis, etc., and using the high-precision three-dimensional shape-modified intensity-modulated radiotherapy technology to give different biological characteristics of the target area. The three-dimensional conformal intensity-modulated radiotherapy technology is utilized to provide radiotherapy with different dosages and segmentation patterns for target areas or sub-target areas with different biological characteristics. Of course, individualized radiotherapy is more dependent on the high-tech technology platform that can provide rapid development and application of imaging technology and laboratory diagnostic technology, precise radiotherapy computer software technology and modern photographic equipment. At present, individualized radiotherapy is still facing many problems, the development of this technology needs to be multidisciplinary, multi-technology and multi-imaging, and needs to be guided by anatomical, pathological and molecular evidence-based guidance, there is still a lot of work to be done, and needs to go a longer way.