For primary malignant tumors of the ovary, the criteria developed by FIGO are now used to estimate prognosis and compare outcomes based on clinical, surgical and pathological staging. The stages of primary ovarian malignancy are as follows: Stage I: tumor is confined to the ovary, and is classified as Ia, Ib and Ic according to whether the tumor is unilateral or bilateral and whether there is tumor on the surface of the ovary or whether there is rupture of the envelope or whether there are malignant cells in the ascites; Stage II: tumor of one or both ovaries with intrapelvic spread, and is classified as IIa, IIb and IIc according to metastasis to different organs and whether there is tumor on the surface of the ovary or whether there is rupture of the envelope or whether there are malignant cells in the ascites. Stage III: One or both ovarian tumors with extra-pelvic peritoneal implantation and/or positive retroperitoneal or inguinal lymph nodes and liver surface metastasis were classified as stage III, and stage IIa, IIb and IIc were classified according to the metastatic site and size of the lesion. There were cancer cells in the pleural fluid and metastasis in the liver parenchyma. In surgery, the tumor stage and the scope of surgery are decided according to the exploration results. For stage Ia and Ib, total hysterectomy and bilateral adnexal resection should be performed. stage Ic and above, simultaneous major omentectomy should be performed. For patients with advanced stage (stage II and above), the primary lesions and metastases should be removed as much as possible so that the residual lesions are less than 2 cm in diameter or no residual lesions are visible to the naked eye, which is called tumor cytoreductive surgery.