【Objective】 To investigate the expression and clinical significance of JunD in molecular subtypes of invasive breast carcinoma，benign and malignant breast lesions.【Methods】Immunohistochemical examination was performed for 160 patients with invasive breast carcinoma，191 patients with breast intraductal proliferative lesions and 20 patients with normal breast tissue.【Results】①Comparison with other subtypes showed that the expression of JunD was significantly increased in TBNC subtype（P＜0.05）and differences between other subtypes were not statistically significant（P＞0.05）. ② The expression of JunD in invasive breast carcinoma was lower than that in breast intraductal proliferative lesions and normal breast tissue（P < 0.01）. ③Based on immunohistochemical staining ，high positive expression rate of JunD was associated with low histological grade（P < 0.01）. There is no correlation between JunD and tumor diameter，age，lymph nodes，ER，PR and histological grade（P > 0.05）.【Conclusions】The expression of JunD was significantly increased in TBNC subtype. To study the expression of JunD in TBNC subtype of invasive breast carcinoma may provide an evaluation in targeted treatment. The different expression of JunD in benign and malignant breast lesions may be helpful for their differential diagnosis.