Objective To investigate the value of MRI, DWI and serum CA125 in qualitative diagnosis of ovarian tumors. Methods Collected MRI and clinical data of 76 patients with ovarian tumors.All cases underwent MR imaging including sagittal T2WI, axial T1WI and T2WI with fat satturation, DWI sequence(b=50,500, 800s/mm2 ) at 1.5 T Siemens MR scanner. In Siemens post-processing workstation analysis of signal characteristics of ovarian tumors, benign and malignant solid tumor measurement part of the ADC values. Results There was a significant difference(P<0.05) between the ADC value comparison about solid parts of ovarian benign (not teratoma)and malignant tumor, the area under the ROC curve for 0.904, the best diagnostic threshold for 1.281×10-3 mm2 /s.In The MRI diagnosis ,the sensitivity, specificity,Youden index and the Kappa value were 80.0%, 92.2%, 72.2% and 0.729, in the MRI combined with serum CA125 diagnosis, the sensitivity, specificity. Youden index and the Kappa value were 88.0%, 94.1%, 82.1% and 0.821. Conclusion The conventional MRI combined with ADC values, and serum CA125 in qualitative diagnosis of ovarian tumor has an important value, can effectively improve the level of differential diagnosis.