Postmenopausal osteoporosis (PMO) at the OP plays a large proportion of high morbidity and mortality in old women seriously affect the quality of life. A longer period of time, PMO prevention and treatment are hormone replacement therapy (HRT)-oriented. However,long-term use of HRT associated with the continuing occurrence of side effects of its application has been questioned and restrictions. Development and research of selective estrogen receptor modulators (SERMs) has aroused great interest, a lot of SERMs (such as tamoxifen and raloxifene) and for clinical. At the same time, long-term use of these drugs will still be some adverse reactions, such as: tamoxifen will increase uterine cancer, hot flashes, the incidence of thrombosis; raloxifene exists apart from nausea, hot flashes, headache, breast pain, such as regular side-effects, but also caused by deep venous thrombo-embolism, it does not apply to have vasomotor symptoms in postmenopausal women. Therefore , selectively researching better, stronger, fewer side-effects of drug prevention and treatment of PMO is to study one of the hotspots. One of the main categories is the one source of isoflavones plants. Genistein (Gen) is an important phytoestrogen. It has a similar structure estrogen and mild estrogen-like biological activity. In vivo and in vitro studies have shown that Gen has a bone protective effect, can promote the proliferation and differentiation of OB. In animal model, Gen can effectively alleviate the castration caused by reduced bone mineral density.Parathyroid hormone (PTH, Parathyroid hormone) regulate calcium metabolism, calcium balance to maintain the body\'s main hormone, its main target organs are bone and kidney. And it showed high expression in bone. Study found that PTH-related protein can effectively promote bone synthesis, and PTH and PTH-related protein can act on the same receptor, namely PTH receptor 1. At present, the patient PMOP parathyroid hormone receptor 1 (PTHR1), compared with the normal existence of differences has not been reported.Firstly,we set up the experiment using ovariectomized female rat model of osteoporosis was observed in rats ovariectomized osteoporosis femur biomechanics and bone mineral density changes in femoral. Detect PTHR1 gene and protein level to explore the PTHR1 on castration-induced osteoporosis the importance of osteoporosis. And on this basis, we given doses of genistein to rats, the establishment of the control group,and at the level of gene and protein detection femur in the expression level of PTHR1. The results show that genistein group PTHR1 expression level is significantly increases, compared to the blank model group, which suggests that genistein treatment PTHR1 receptors are one of the possible ways at PMO process.