Objective To investigate the diagnostic efficiency of patients with human epidermal growth factor receptor-2(HER-2)over expressed breast cancer via combining the dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)perfusion parameters,apparent diffusion coefficient(ADC)value and clinical feature model.Methods A total of 197 breast cancer patients who underwent DCE-MRI and diffusion weighted imaging(DWI)scans were analyzed retrospectively,including 47 breast cancer patients with HER-2 over expressed and 150 breast cancer patients with non-HER-2 over expressed.The t-test or chi-square test was used to compare the DCE-MRI perfusion parameters[Ktrans,Kep,Ve,W-in,W-out,and time to peak(TTP)],ADC value,and clinical feature between the two groups.The diagnostic efficiency of the models were analyzed via receiver operating characteristic(ROC)curves.Results There were significant difference in the maximum tumor diameter,minimum tumor diameter,T stage,N stage,Kep,W-in,and ADC value between HER-2 over expressed breast cancer and non-HER-2 over expressed breast cancer groups(P＜0.05).The proposed combined model,which included the combined maximum tumor diameter,minimum tumor diameter,T stage,N stage,Kep,W-in,and ADC value,showed a better diagnostic efficiency with area under the curve(AUC)(AUC=0.763)than the clinical model(AUC=0.634)based on the combined maximum tumor diameter,minimum tumor diameter,T stage,and N stage,and the imaging model(AUC=0.715)based on the combined Kep,W-in and ADC value.Conclusion The maximum tumor diameter,minimum tumor diameter,T stage,N stage,Kep,W-in,and ADC value may be associated with HER-2 over expressed breast cancer.Combining all above parameters can improve the diagnostic ability of breast cancer patients with HER-2 over expressed.