Objective: To validate the value of IOTA simple rules (SR) in differential diagnosis of malignant and benign ovarian tumors preoperatively in a single center in Chinese population. Methods: A total of 278 patients admitted for ova-rian tumors surgery in Department of Obstetrics and Gynecology, Ruijin Hospital were enrolled. All patients underwent ultrasound examination preoperatively, and 278 ovarian tumors were detected and classified as malignant (including 75 cases of borderline), benign lesions (175 cases) and uncertain lesions (37cases) using SR. Compared with the results of postoperative pathology examination, the sensitivity, specificity of SR in diagnosing malignant tumor as well as the area under receiver operating characteristic (ROC) curve were calculated. Results: The postoperative pathology examination showed that there were 203 benign tumors and 75 malignant ones. It indicated that SR identified 86.2% benign tumors (175 out of 203) and 68.0% malignant tumors (51 cases out of 75), 15 cases were missed or misdiagnosed and 37 cases got uncertain results. Among ultrasonic features of SR, M4 (irregular multilocular-solid tumor with largest diameter ≥100 mm) had the highest predictive value (90.5%) for malignant tumors, while B3 (acoustic shadow) had the highest predictive value (100.0%) for benign tumors. In 241 patients (excluding uncertain cases), the sensitivity and specificity of SR in diagnosing ovarian tumors was 86.4%, 96.2%, respectively. In 278 patients, as the uncertain cases diagnosed with SR were classified to be malignant tumors, the sensitivity was 89.3%, specificity was 86.2%, and AUC was 0.88. However, as uncertain cases were classified to be benign ovarian, the sensitivity and specificity of SR in diagnosing tumors was 68.0% and 96.6%, and the AUC was 0.82. The efficacy between the two methods was different(P=0.04). Eight benign cases were misdiagnosed as malignancy, and the review showed that the possibility of malignancy should be considered when the inner wall of the cystic mass was not smooth, papillary processes attached to the wall, or the size of cystic mass was more than 10 cm. Seven malignant cases were misdiagnosed as benign ones. It indicated that benign mass should be considered when the solid part had insufficient blood supply or even no blood flow on ultrasound imaging. Conclusions: SR is suitable to be applied to Chinese female in diagnosing ovarian tumor. IOTA SR may have better efficacy when the uncertain cases diagnosed with SR are classified as malignant tumors