Seminoblastoma is a malignant tumor that is better treated with radiation therapy. The number of radiotherapy for spermatogonial cell tumor is not necessary 15 times, it is based on the different stages of the disease, i.e., stage I, stage II, stage III and stage IV to adopt different radiotherapy strategies. 1. Stage I: after surgery, patients with stage I spermatogonial cell tumor need 1-2 times of radiotherapy for lateral iliac lymph nodes and retroperitoneal lymph nodes, which can prevent the possibility of cancer recurrence. 2. Stage 2: when the patient is in stage 2, the cancer cells have metastasized, and the spermatogonial tumor needs whole abdomen irradiation treatment for 3-6 times to check and control the cancer cells metastasizing again. 3. Stage III: the metastasis of spermatogonial cell tumor in Stage III is faster and has irregularity, then it needs to be treated by increasing the number of mediastinal lymph node radiation therapy, and it can be effectively controlled by 9-12 times. 4. Stage IV: for patients with stage IV, the lesion of seminoma is relatively serious, the cancer cells have been widely metastasized, the effect of radiotherapy is weakened, and chemotherapy-based treatment is needed, and radiotherapy is a kind of auxiliary to chemotherapy. Radiation therapy is an adjuvant to chemotherapy. 15 times of radiation therapy for spermatogonial cell tumor is not fixed, it needs to be analyzed according to the patient’s condition, and the specific situation still needs to follow the doctor’s guidance.