Abstract: Objective To investigate whether the Hedgehog (Hh) signaling pathway is activated in human breast cancer. Method we determined the expression of the components, including Sonic Hh, Patched1, and Gli1,Smo of the Hh pathway by immunohistochemical staining in a series of 64 human breast carcinomas. Result In the 64 tumor specimens,there are 64（100％），61（95.3％），62（96.9％）,and 61（95.3％）highly express protein Shh ,Patched1 and Glil,Smo respectively,while in the adjacent nomal mammary tissue, correspondingly,those protein are not or weakly express at can detect level.So,the Hedgehog (Hh) signaling pathway is activated in human breast cancer commonly,which has no relative to lymphoid node metabasis，or size of carcinomor, but maybe connect with some special histologic type. All of 64 tumors displayed staining of high intensity for Gli1 when compared with adjacent normal tissue. The ratio of nuclear positive staining of Gli1/all the tumor cell is range from 2%－95%,median at 40.87%. The nuclear staining of Gli1 correlated with expression of estrogen receptor (P<0.05），but has no relative to progesterone receptor。Conclusion These data indicate that the Hh pathway is a new candidate for therapeutic target of breast cancer.