Objective To investigate the relationship between single b-value and multiple b-value diffusion weighted imaging (DWI)and different types of breast lesions.Methods The data of 92 cases including 8 cases of cyst,11 cases of granulomatous inflammation,33 cases of benign nodules lesions and 40 cases of malignant tumor were analyzed retrospectively,who underwent single b-value DWI and multiple b-value DWI and all patients were confirmed by pathology.The normal side of the mammary gland fiber was taken as the control group.Apparent diffusion coefficient(ADC)were obtained by the monoexponential model.Slow apparent diffusion coefficient(ADCslow),fast apparent diffusion coefficient(ADCfast),the fraction of fast ADC(ffast)were obtained by the biexponential model.ADC,ADCslow,ADCfast,ffastvalues of different breast lesions were analyzed by single factor analysis of variance.The LSD-t test was used to compare the mean values of the parameters of the breast lesions in pairs.Results The ADC and ADCslowvalue of breast lesions were decreased in the order of cyst (2.369 ± 0.380)×10-3mm2/s,(1.294 ± 0.439)×10-3mm2/s,normal gland(1.785 ± 0.298)×10-3mm2/s,(0.946 ± 0.321)×10-3mm2/s,benign tumor(1.647 ± 0.296)×10-3mm2/s,(0.944 ± 0.256)×10-3mm2/s,malignant tumor(1.146 ± 0.191)×10-3mm2/s,(0.584 ± 0.139)×10-3mm2/s and mastitis(1.062 ± 0.231)×10-3mm2/s,(0.567 ± 0.115)×10-3mm2/s.The ADCfastvalue of malignant group(4.445 ± 1.616)×10-3mm2/s was significantly higher than that of other groups,and the difference was statistically significant.The ffastvalue of malignant group 0.364 ± 0.148 was significantly lower than that of benign group,normal gland and cyst.ADCfastvalue in the inflammatory group(3.321 ± 0.660)× 10-3mm2/s was significantly lower than that in the malignant group,and the difference was statistically significant.There was no significant difference in ADC,ADCslowand ffast.Conclusion Compared with the single b-value DWI,the parameters of multiple b-value DWI reflected the pathological features of different breast lesions better.The value of ADCfasthas higher diagnostic value in the identification of mastitis and breast cancer.