Ovarian malignancy is one of the common malignant tumors of female reproductive organs, ranking third in incidence after cervical cancer and uterine corpus cancer. However, the mortality rate of ovarian epithelial cancer is the first among all types of gynecological tumors, posing a serious threat to women’s lives. Due to the complexity of ovarian embryonic development, tissue anatomy and endocrine function, and the atypical early symptoms, it is quite difficult to identify the tissue type, benign and malignant of ovarian tumors before surgery. Among ovarian malignant tumors, epithelial carcinoma is the most common, followed by malignant germ cell tumors. Most of them have spread to the uterus, bilateral adnexa, greater omentum and various pelvic organs, so it is a big problem in early diagnosis. The prevention of ovarian cancer mainly focuses on epithelial ovarian tumors: 1. Taking oral contraceptives can reduce the risk of ovarian cancer by 60% compared with women who have never taken contraceptives, if they take contraceptives for more than five years. 2. Encourage breastfeeding and prolong breastfeeding time. 3.Diet: eat more vegetables and fruits and less high-fat food, especially animal fat. 4.Preventive guidance for women with family history of ovarian cancer: genetic counseling and genetic testing. 5.Preventive oophorectomy: Patients over 40 years old with a family history of ovarian cancer can sometimes be advised to have their ovaries surgically removed.