Normal women may also have a small amount of pelvic fluid, which is caused by the collection of fluid between abdominal cavity and gastrointestinal tract in the rectal sink of uterus. Generally, if the amount of pelvic fluid exceeds 200mL, it can be called ascites. At this time, other examination indexes of ovarian cancer, such as CT, MRI of pelvic and abdominal cavity or clinical staging of surgery, should be combined to determine the stage of tumor, and the final stage of ovarian cancer should be determined based on the excised tissues sent to pathological examination and ascites to find tumor cells during surgery. According to clinical experience, the more the amount of ascites, the faster it is formed, the more likely it is caused by the massive exudation of ovarian cancer in the advanced stage, or the rapid increase of ascites, or even bloody change, caused by the malignant tumor cells of ovarian cancer penetrating the peritoneum and metastasizing to the pelvic and peritoneal cavities.