Abstract: Objective To compare the utility of contrast-enhanced spectral mammography (CESM) and magnetic resonance imaging (MRI) in the diagnosis of breast cancer. Methods From January,2016 to September,2016,a total of 40 women with breast cancer confirmed by pathology were enrolled as research object to performed with CESM and BMRI.Age ranged was from 32 to 76 years,with an average age was (48.6±11.7) years.No pregnant,without receiving the mastectomy,or breast reconstruction,without chemotherapy,or shown to iodine contrast agent or other contrast agent allergy.There were 53 piece of lesions in 40 patients,including 32 piece of lesions in 22 cases of infiltrating ductal carcinoma;7 piece of lesions in 7 cases of mixed tumor;5 piece of lesions in 5 cases of invasive lobular carcinoma;3 piece of lesions in 3 cases of invasive adenocarcinoma;2 piece of lesions in 1 cases of intraductal carcinoma;2 piece of lesions in 1 cases of leaf tissue tumor of the breast meat;2 piece of lesions in 1 cases of papillary carcinoma.The average maximum dimensions of the lesions were measured.The differences in sensitivity,specification,accuracy,positive predictive value and negative predictive value were compared between the two methods. Results Fifty-there lesions were identified.The mean size of lesions tested by CESM and MRI were (32.7±27.7) mm and (33.4±29.5) mm,which show no differences between the two methods (P>0.05).CESM sensitivity was 100%(vs.97.4% for MRI),specificity was 66.7%(vs.53.3% for MRI),accuracy was 90.6%(vs.84.9% for MRI),positive predictive value was 88.4%(vs.84.1% for MRI),and negative predictive value was 100%(vs.88.9% for MRI) for breast cancer diagnosis.There was no statistically significant difference between the two methods for the diagnostic indexes (P>0.05). Conclusion Compared with MRI,CESM can provide great sensitivity,specification,accuracy,PPV and NPV,which has potential application value in breast cancer detection.