Objective To analyze the diagnostic value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) for benign and malignant cystic ovarian tumors. Methods The clinical data of 120 patients with cystic ovarian tumor confirmed by surgery and pathology in our hospital were collected. All patients were treated with routine MRI scan, DCE-MRI and DWI scan, the imaging features were analyzed, the apparent diffusion coefficient (ADC), volume transport parameter (Ktrans), rate constant (Kep), extravascular extracellular space volume ratio (Ve) in benign and malignant cystic ovarian tumors were compared, the diagnostic efficacy was evaluated. Results Among the 120 patients, there were 67 (55.83%) with malignant lesions and 53 (44.17%) with benign lesions. The ADC value of solid part of cystic ovarian malignant tumor was significantly lower than that of benign tumor (P<0.05). There was no significant difference between cystic part ADC and benign tumor (P>0.05). When ADC equaled to 1.20×10-3mm2 /s, the diagnostic sensitivity and specificity were 86.57% and 81.13%, respectively. The Ktrans, Kep and Ve values of solid parts of cystic ovarian malignant tumors were significantly lower than those of benign tumors (P<0.05). When Ktrans equaled to 0.09min-1, the diagnostic sensitivity and specificity were 83.58% and 83.02%, respectively. The diagnostic sensitivity, specificity, accuracy, positive predictive value and negative predictive value by DCE-MRI combined with DWI for benign and malignant cystic ovarian tumors were 94.03%, 94.34%, 94.17%, 95.45%, and 92.59%, respectively, all higher than the values by DCE-MRI alone and DWI alone. Conclusion DCE-MRI combined with DWI has a good diagnostic effect on benign and malignant cystic ovarian tumors, it can be used as an important method for preoperative diagnosis of cystic ovarian tumors.