Objective: By testing the levels of CA125 and EmAb in serum and ovarian cyst fluid ,to study the relationship between CA125 and EmAb with endometriosis ,and to find its value of diagnosis , development and treatment in endometriosis.  Methods: Selecting the patients with ovarian cysts from Department of Gynaecology of the first affiliated hospital of Guangxi Medical University during the period from November 2004 to April 2005 at random. Taking the patients who were operated by Laparoscope and through abdomen as study group, these patients were confirmed as endometrial cysts of the ovary(ECO) by pathological diagnosis. The patients with non-endometrial cysts of the ovary were control group. Blood samples were collected from all patients involved before operating, and the fluid of ovarian cysts were collected during the operating , CA125 and EmAb levels in serum and fluid of ovarian cysts were tested respectively by microparticle enzyme immunoassay(MEIA) and enzyme linked immunosorbent assay(ELISA).  Results: The mean CA125 concentration in the fluid of ECO was remarkably higher than that of the serum(p0.05). The serum and the fluid CAl25 level