Prostate cancer is one of the malignant tumors that men are prone to, and its incidence rate remains high in developed countries such as Europe and the United States, and the incidence rate in China is also increasing year by year, especially in large and medium-sized cities, where the growth rate of new cases of prostate cancer is at the top of male malignant tumors. It is foreseeable that the incidence of prostate cancer and the number of new cases will increase significantly in the coming decades. Therefore, the prevention and treatment of prostate cancer should be of great importance to the society and families. The treatment of prostate cancer, like most tumors, is surgical treatment. With the development of science and technology, a large number of cases have confirmed that radiation therapy and surgery have been comparable in terms of long-term survival index, and radiation therapy has become the main method of comprehensive treatment for prostate cancer as patients have fewer complications and better quality of life. The technology of radiation therapy for prostate cancer has a history of less than one hundred years, but it has developed very rapidly. Over the past hundred years, radiation therapy for tumors has gone through the course of primary radiotherapy and conventional radiotherapy, and has entered a new stage of modern radiotherapy. As early as 1915, Young used radium radiation to treat prostate cancer, and in 1920, Barringer inserted radium needles into the prostate gland for treatment, and in 1942, he performed pathological examinations on patients 6 or 7 years after treatment and found that the tumors disappeared after radiation therapy. However, in 1941, Huggins and Hodge discovered that prostate cancer was androgen-dependent, and scholars shifted their main focus to endocrine therapy, and radiation therapy for prostate cancer was interrupted. In the 1950s, after years of research on endocrine therapy for prostate cancer, people began to realize that endocrine therapy was only a palliative treatment that could neither cure prostate cancer nor prolong the life of the patient. With the introduction of 60Co and linear gas pedals, research and clinical applications of various radiation therapies began. Bagshaw of Stanford University, USA, was the first to investigate radiation therapy as a radical treatment for prostate cancer. He followed up 1031 prostate cancer patients with radiation therapy for 32 years, and did pathological biopsy studies on 83 of them. A large number of facts proved that radiation therapy is a very effective and safe treatment for limited prostate cancer. Through the observation of several important indicators such as local control rate and long-term disease-free survival rate, it was found that radiation therapy achieves the same efficacy as surgical treatment, and patients with radiation therapy retain their prostate gland with normal tissue structure and morphology, less complications and improved quality of life of patients. At the end of the last century, with the high development of computer technology, radiation therapy has a new change, with epochal significance is the conformal intensity adjustment technology. Through CT simulation positioning, precise outline of the target area, the application of radiation treatment planning system (TPS) reverse design, coupled with the flexible and versatile multi-leaf grating to adapt to the shape of the tumor, the use of high-energy radiation irradiation tumor, to achieve the purpose of eliminating the tumor to protect normal tissues and organs. Precise positioning, precise planning and accurate irradiation are the core elements of conformal intensity modulated radiotherapy technology. The radiation dose for prostate cancer has increased from 64 to 81 Gy, the efficiency has increased from 46% to 88%, and the radiation damage has decreased from 17% to 2%, which can achieve the ideal effect of radiation therapy to cure prostate cancer. The indications for radiation therapy for prostate cancer are as follows: ① Radical radiotherapy is suitable for limited prostate cancer; ② Adjuvant radiotherapy is needed for residual prostate cancer after surgery or T3 stage prostate cancer; ③ Radical radiotherapy is needed for cancer found in histopathology (called incidental cancer) after using electrodesiccation for prostate hyperplasia; ④ Radical radiotherapy is needed for prostate cancer that is not treated with depot and endocrine therapy; ⑤ Radical radiotherapy is needed when prostate cancer has bone metastasis, (4) Radical radiotherapy is needed for prostate cancer that is not treated with debulking and endocrine therapy; (5) Palliative radiotherapy is needed for prostate cancer with bone metastasis, hematuria, and lower urinary tract obstruction, which can relieve pain, hemorrhage and symptoms. In conclusion, radiation therapy has become one of the safe and effective treatment methods for prostate cancer, and scientific and reasonable radiation therapy can achieve clinical efficacy comparable to that of surgery, with fewer complications and high quality of life. The development of computer-aided three-dimensional conformal intensity modulation technology enables more accurate tumor localization, increases the dose of radiation to the tumor target area, reduces the dose to the surrounding normal tissues such as the bladder and rectum, effectively improves the local control rate of tumor and reduces complications for the benefit of prostate cancer patients. With the development and application of more and more advanced radiotherapy techniques, it is believed that the treatment effect of prostate cancer will be even more improved. The following is a diagram of the intensity-modulated radiotherapy plan for prostate cancer