Mechanical signaling plays a critical role in bone growth, remodeling and healing. Recent studies discover that estrogen can modulate proliferation, apoptosis and functional activity of bone cell tissues via estrogen receptor (ER) and affect bone formation and absorption. Thus ER plays an important role in bone growth and remodeling. ER also involves in the adaptive response to mechanical stimulation, which is affected by ER numbers and activity. These findings suggest that mechanical stimulation and estrogen can act together to regulate functions of bone cells via common signaling pathways. In this review, the role and mechanism of ER in bone tissues and its respons to mechanical stimulation are discussed.