Objective To explore the differential diagnostic value of IOTA, CDFI and CA125 for benign and malignant ovarian tumors.Methods A retrospective analysis of 89 patients undergoing gynecological surgery in the Fourth Affiliated Hospital of Harbin Medical University from September 2018 to January 2020.All patients were confirmed to be ovarian tumors by preoperative ultrasound. Collecting two-dimensional ultrasound characteristics, medical history and serum Tumor marker CA125, and using pathological results as the "gold standard" to analyze IOTA simple rules, CDFI classification, serum CA125 indicators respectively, and the three combined diagnosis of benign and malignant ovarian tumors. The accuracy, sensitivity, and specificity of the diagnosis are combined Evaluate diagnostic efficacy. Results Compared with patients with benign tumors, the ultrasound images of patients with ovarian malignant tumors,including morphology, borders, internal components, presence or absence of papillary protrusions, RI, blood flow velocity, and blood flow location, had statistically significant differences (P<0.05) . The diagnostic accuracy of the simple rules of IOTA was 74.16% ; the accuracy of CDFI classification was 79.78%; the best cut-off value of serum CA125 was 45.25KU/L, and the diagnostic accuracy was 75.28%; the diagnostic accuracy rate of the combined diagnosis of the three is 89.89%. The AUC of IOTA simple rules, CDFI classification, serum CA125 and the combination of the three were 0.863, 0.786, 0.744, 0.894. Compared with the combination of the three, the CDFI classification , serum CA125 alone had statistically significant difference(P＜0.05). Conclusion IOTA simple rules, CDFI classification, and serum CA125 levels are effective indicators for diagnosing benign and malignant ovarian tumors; IOTA simple rules have good diagnostic efficiency; the combination diagnosis of IOTA simple rules, CDFI classification and serum CA125 can further improve the diagnostic accuracy and specificity.