Abstract: Objective To study the effects and mechanism of estrogen on growth and development,serum biochemical indexes,bone mass and uterus hyperplasia in ovariectomized rats that imitated postmenopausal women.Methods Four-month-old SD rats were sham-operated or ovariectomized by abdominal cavity operation and divided into sham,Ovx,and estrogen group(EC)and feed 7 weeks.During the experiment,the rats weight and food intake were recorded,the food utilization rates of each group were calculated.Serum biochemical indexes,bone mineral density(BMD),calcium content and uterus hyperplasia were measured.Results The weight and food utilization rate of EC group decreased significantly(P<0.01).The BMD of EC group was higher than Ovx group(P<0.05).The uterus of EC group was not seen atrophy.Conclusion Estrogen could significantly inhibit Ovx induced weight gain,and were effective in preventing bone mass loss induced by ovariectomy and the uterus hyperplasia effection was also significantly.