We evaluated the protective effect of Psoralea corylifolia L. (PCL) extract on the ovariectomized (OVX) rat model. The biochemical markers of bone turnover, calcium metabolism, and calcium balance were examined. PCL extract (25 mg or 50 mg/kg body weight/day) was orally administrated to OVX rats for 3 months. PCL extract did not alter weight gain or uterus weight in OVX rats. PCL extract significantly increased serum Ca (calcium) levels (p < 0.05, vs. OVX group) as well as decreased urinary Ca excretion (p < 0.05 vs. OVX group) in OVX rats. The upregulation of serum osteocalcin level by ovariectomy was suppressed by treatment with PCL extract in rats (p < 0.05, vs. OVX group). PCL extract increased bone mineral density at 50 mg/kg body weight/day in OVX rats (p < 0.05, vs. OVX group). Our results indicate that orally administrated PCL extract can decrease urinary calcium excretion and decrease serum osteocalcin in OVX rats, resulting in positive effects on bone mineral density as well as bone formation. In conclusion, our studies showed that PCL might be a potential candidate for treatment of postmenopausal osteoporosis.