Objective Bone loss due to estrogen deficiency can be prevented by estrogen replacement therapy. But it produces a number of side effects associated with the cancer of breast and uterus which limits its application. Selective estrogen receptor modulators(SERMs) are a new category of therapeutic agents, they could bind to estrogen receptors with high affinity and mimic the effects of estrogen in some tissue but act as estrogen antagonists in others. This study was designed to observe the effect of Raloxifene on osteoporosis of the OVX rat model and probe into its mechanism. Methods Thirty-two 3-month-old female SD rats were randomly divided into four groups: the basal control, the OVX, OVX with RLX,OVX with DES. All rats were killed at the end of the experiment five months later. Body weight, bone mineral density (BMD), bone histomorphometry, uterine weight were measured. Results BMD of total body, lumbar spine and femur in OVX rats was significantly lower than that of rats treated with RLX by decreasing 21%, 35%, 40%, respectively. The number of osteoclast was significantly decreased in RLX-treated-OVX rats compared to OVX rats (P