There are many histologic types of ovarian tumors, which are usually classified as tumors of epithelial origin in the corpora cavernosa, sex cord mesenchymal tumors, germ cell tumors, and metastatic tumors. Germ cell tumors are a group of ovarian tumors derived from primitive germ cells, the most common being ovarian teratomas. Most of the ovarian teratoma tumor tissue is mature and a few are immature. The benign or malignant nature of the tumor and the degree of malignancy depend on the degree of tissue differentiation. For mature teratoma, it is a benign tumor and the most common ovarian tumor, occurring at any age, with a malignant rate of 2-4%, mostly occurring in postmenopausal women. According to the patient’s age, fertility requirements and the condition of the contralateral ovary to determine the scope of the operation, the young patients will be performed on the affected side of the adnexa resection or teratoma debulking surgery, perimenopausal women can be performed on the whole uterus and double adnexa resection, the tumor will be dissected to observe benign and malignant, and if necessary, frozen section histology will be performed. If necessary, frozen section histological examination is done to determine the scope of surgery; immature teratoma is a malignant tumor, occurring in adolescents, and the principle of treatment is mainly surgery, plus chemotherapy. According to the results of intraoperative exploration, the tumor staging and surgical scope should be decided. The recurrence and metastasis rates are high. However, after recurrence and reoperation, the malignant degree can be reversed. Ovarian teratoma can be benign or malignant, and should be treated according to different conditions.