Objective To explore the clinical value of CDFI blood flow grade and systolic to end-diastolic velocity ratio（S/D） in differential diagnosis of benign and malignant ovarian tumors.Methods A total of 96 patients with ovarian cancer（case group） and 96 patients with benign ovarian disease（control group） diagnosed in our hospital were selected

the blood flow grade and S/D value were determined by CDFI.Based on the pathological examination

the receiver operating characteristic（ROC） curve was drawn to evaluate the blood flow grading and the S/D value and the effectiveness of the two parameters in differentiating benign and malignant ovarian tumors.Results The blood flow grade and S/D values of case group were significantly higher than those of control group

and the differences were statistically significant（both P<0.05）.The sensitivity

specificity and accuracy of the differentiation of the benign and malignant ovarian tumors were 81.25%

83.33% and 82.29% when the blood flow grade was≥Ⅱ.The sensitivity

specificity and accuracy of the differentiation of the benign and malignant ovarian tumors were 87.50%

81.25% and 84.38% when the S/D value≥2.20

When the two were combined

the sensitivity

specificity and accuracy of differentiation of ovarian benign and malignant tumors were 95.83%

93.75% and 94.79%

respectively

which were significantly higher than those of the single application

and the differences were statistically significant（all P<0.05）.Conclusion CDFI blood flow grade and S/D value have good diagnostic efficacy in differentiating benign and malignant ovarian tumors

and their combined application can further improve the diagnostic accuracy.