Abstract: Objective: To detect the expression of Galactose lectin 3(Galectin-3) and its relationship with clinicopathological features and human epidermal growth factor receptor-2(Her-2) in breast infiltrating ductal carcinoma.Methods: The expression levels of Galectin-3 and Her-2 in 70 breast infiltrating ductal carcinoma tissue samples were detected by immunohistochemical method.The Her-2 gene expression was detected by fluorescence in situ hybridization.The relationships between the expression of Galectin-3 with the patient age,tumor size,lymph node metastasis,histological grade,clinical stage and Her-2 expression were investigated.Results: The positive rate differences of Galectin-3 expression in different age and tumor size breast cancer tissue had no statistically significant(P>0.05).The positive rate of Galectin-3 expression in sample with lymph node metastasis was higher than that in sample without metastasis(P<0.05).The positive rate differences of Galectin-3 expression in different histological grade and clinical stage had statistically significant(P<0.05).The positive rate of Galectin-3 expression was higher than Her-2 expression in breast cancer tissue(P<0.05).Conclusions: Galectin-3 plays an important role in the occurrence,development,invasion and metastasis of breast cancer.Detecting the expression of Galectin-3 in breast cancer can contribute to judge the malignant degree and prognosis of tumor,which maybe become an important index in guiding clinical treatment.