Objective  To explore the expression of CA125 of epithelial ovarian cancer (EOC) and its correlation with the prognosis. Methods  The clinical data of 247 cases that diagnosed with EOC were retrospectively analyzed. All patients were followed up for at least 5 years or till they were dead. CA125 levels were detected by chemiluminescence immunoassay and divided into four intervals, i.e. q1, q2, q3, and q4. The differences of expressions of CA125 of patients with different clinical features and the survival of patients with CA125 levels within four intervals were compared. The prognosis factors were analyzed by Logistic regression analysis. Results  The differences of expressions of CA125 of patients with different age, pathological type, FIGO staging, histological differentiation, and postoperative residual lesion size were statistically significant (P<0.05). The median survival time of the four intervals (q1,q2,q3, and q4) were 58, 40, 19, and 11 months and 5-year survival rates were 48.4%(30/62), 32.3%(20/62), 21.0%(13/62), and 11.5%(7/61). The differences were statistically significant (P<0.05). Logistic regression analysis showed that compared with q1, OR (95%CI) of prognosis of death of q2, q3, and q4 were 1.624 (1.445-1.825), 2.447 (1.785-3.355) and 4.121 (2.624-6.472), respectively. Conclusion  The expression of CA125 is correlated with different clinical pathological characteristics of patients with epithelial ovarian cancer. Preoperative CA125 level may be an independent predictor of prognosis of epithelial ovarian cancer.