Radiation therapy for prostate cancer has the advantages of good efficacy, broad indications and few complications, and is suitable for patients at all stages. Radical radiation therapy for early stage patients has a local control rate and 10-year disease-free survival rate similar to that of radical prostate cancer surgery. It is currently considered one of the three methods that can cure early prostate cancer (radical prostatectomy, external radiation therapy for prostate cancer, and internal radiation therapy for prostate cancer). In recent years, techniques such as three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) have been gradually applied to the treatment of prostate cancer and have become the mainstream techniques of radiotherapy. 3D-CRT and IMRT are used to map out the geometric model of the target area and normal tissues and create a digital reconstruction, so that the dose of external irradiation can reach a higher degree of conformality and achieve the accuracy of “spot removal”. In this way, the local dose of tumor irradiation and the total amount of target area irradiation can be increased while minimizing the irradiation to the surrounding normal tissues and organs, which improves the local control rate of tumor and reduces the complications of radiation therapy.