Objective To study the value of multi-modal magnetic resonance imaging (MRI) combined with mammography and ultrasound in the differential diagnosis of benign and malignant breast lesions. Methods 83 patients with breast space occupying lesions who were admitted to our hospital during the period from June 2015 to June 2017 were selected as the subjects. All of them underwent histopathological examination, and the mammography, ultrasound and MRI examinations were performed at 2 weeks before operation or biopsy. The sensitivities, specificities, positive predictive values, negative predictive values and total coincidence rates of mammography, ultrasound, multimodal MRI, multi-modal MRI combined with mammography and ultrasound were calculated with the pathological results of operation or biopsy as the golden standard. Results Operation or biopsy of the 83 patients with breast space occupying lesions found that there were 60 cases with benign breast lesions and 23 cases with malignant breast lesions. The sensitivity, specificity and coincidence rate of mammography were 73.9%, 76.7% and 75.9%, respectively, those of ultrasonography were 82.6%, 83.3% and 83.1%, respectively, those of multi-modal MRI were 87.0%, 88.3% and 88.0%, respectively, and those of multi-modal MRI combined with mammography and ultrasonography were 100.0%, 95.0% and 95.4%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value and the total coincidence rate of multi-modal MRI combined with mammography and ultrasonography were significantly higher than those of mammography in the diagnosis of benign and malignant breast lesions(P<0.05). The specificity, positive predictive value and the total coincidence rate of combined examination were significantly higher than those of ultrasound (P<0.05), and the total coincidence rate was significantly higher than that of multi-modal MRI examination (P<0.05). Conclusion Mammography, ultrasound and multi-modal MRI have their own advantages and disadvantages. Combined examination can improve the diagnostic coincidence rateof benign and malignant breast lesions, providing imaging evidences for diagnosis and intervention of breast space occupying lesions.