Ovarian germ cell tumors are most commonly seen in children and young women. This tumor can originate from both male and female gonads, and can also originate from outside the gonads, making its pathological organization complex. Norris (1992) classified them as: 1. germ cell tumors, which are subdivided into asexual cell tumors, yolk sac tumors, teratomas, embryonal carcinomas, primary choriocarcinomas, and combined germ cell tumors. 2.Mixed germ cell and gonadal mesenchymal tumors, which are further classified into gonadoblastoma and others. 3.Germ cell tumors occurring in dysplastic gonads. This tumor occurs in young people, and the younger the age, the greater the possibility of malignancy. When pelvic tumors occur in children, adolescents and young women, malignant germ cell tumors of the ovary should be excluded first. Immature teratoma of the ovary is less common, accounting for the third most malignant germ cell tumor and less common than anaplastic cell tumor and yolk cystic tumor, which are more malignant and prone to metastasis and recurrence. The disease occurs mostly in young patients. However, immature teratoma of the ovary is still a highly malignant tumor and has a high mortality rate if not treated properly. The principles of treatment for immature teratoma of the ovary are: (1) first perform tumor cytoreductive surgery to make the tumor ≤2 cm in diameter if possible; (2) use effective combination chemotherapy as soon as possible after surgery. Embryonal carcinoma, endodermal sinus carcinoma, primary choriocarcinoma and immature teratoma are all highly malignant germ cell tumors that cannot be treated with monotherapy and must be treated with combination therapy. The relevant drugs that make up these combination therapies are: vincristine, actinomycin D, cyclophosphamide, cisplatin, vincristine, bleomycin, onychomycin, cisplatin, vincristine, fluorouracil, methotrexate, VP16, etc. The principle of treatment for ovarian malignant germ cell tumors should be a comprehensive treatment mainly based on surgery, whether it is early or late stage. Metastasis and spread are not contraindications to surgery. The tumor lesions visible to the naked eye should be removed or tumor cytoreductive surgery should be performed as far as possible, and the residual foci should be <1-2cm. 2. Most germ cell tumors are unilateral, and contralateral involvement is rare. Therefore, unilateral adnexal resection should be considered as the scope of surgery, and simple tumor debulking should not be performed. The healthy ovary and uterus should be preserved. Prophylactic resection of the healthy ovary and uterus does not play a significant protective role in reducing recurrence. 3. Malignant germ cell tumors of the ovary are more sensitive to chemotherapy, and surgery plus chemotherapy is more effective. 4. For malignant germ cell tumor of ovary with stage II or above, one side of the adnexa should be removed and cytoreductive surgery including the greater omentum should be performed at the same time. 5. Surgery to preserve reproductive function is not limited to stage I and II patients, but can also be considered for stage III and IV patients, and chemotherapy alone may also cure the disease. 6.For ovarian immature teratoma, after the initial surgery, combined chemotherapy must be used early to prevent recurrence and improve survival rate, and repeated surgery can be performed for patients with recurrent recurrence. Combination chemotherapy with milder reaction and lesser course of treatment should be chosen after surgery. For patients with stage I or above, they can choose: (1) 12 courses of VAC program; (2) 6 courses of PVB or BEP case; (3) 3 courses of PVN program followed by 6 courses of VAC program. 7. Patients with preserved fertility must be followed up closely. After discontinuation of chemotherapy, menstruation can generally be normalized and pregnancy can be considered after 3 months. 8.Patients with immature teratoma of ovary, if there are still residual toadstools after the first operation, those who have not been completely relieved after chemotherapy, or those who have recurred after treatment, secondary reduction should be actively performed. Because immature teratoma has the characteristics of transformation from immature to mature, from hypodifferentiated to highly differentiated, and from malignant to benign, the time of transformation takes about 1 year. Therefore, it is necessary to perform multiple surgeries and then supplement with chemotherapy for these patients. The rate of lymph node metastasis in patients with ovarian immature teratoma is as high as 25%, and there is a tendency of metastasis at an early stage. The main treatment is surgical removal, preferably including a section of the lumbar lymph nodes below the branches of the inferior mesenteric artery.