The paper studies the post-operation radiotherapy on 146 cases of malignant ovarioneus from 1965 to 1985. 45 cases out of 146 are young women with 27 cases of germinoma, which is 58. 6% among 46 cases. Among 27 cases of germinoma, 21 cases, that is 77%, are dysgerminoma. Because germinoma is sensitive to the radiotherapy, post-operation radiotherapy should be conducted to inerease the immortality rate, though germinoma is widely spread to lymphatic ducts. Ihe paper studies the 46 cases of malignant ovarioncus with post-operation radiotherapy and concludes that the survival rate for 5 years is 52.17% (24/46), whieh is comparatively higher than those reported in other reports.