Objective:To investigate the relationship between obesity and estrogen and their impact on uterus. Methods:Totally 48 rats were randomly divided into the following six groups:normal diet group(A),the high－fat diet group(B),uterectomy and normal diet group (C),uterectomy and high－fat diet group (D),estrogen supplement and normal diet group (E),estrogen supplement and high－fat diet group (F). The weight of the SD rats was tested weekly. The IPGTT experiment were taken after 14 weeks, and the experiment rats were executed after 16 weeks. The biochemical indicators were measured and the appearance of the uterus and the histological changes of different groups of the rats were compared. Results:Lack of estrogen increased the body weight and visceral fat content. TG,GLU,UA levels were negatively correlated with the estrogen level,while TG level was positively correlated with obesity. But there was no significant differences among these groups. The deficience of estrogen was associated with the insulin resistance,and the replacement of estrogen elevated insulin sensitivity and reduced blood glucose. The absence of estrogen led to analosis of uterus,and estrogen supplement significantly promoted the growth and development of uterus. Estrogen and obesity are both positively correlated with endometrial proliferation. Conclusion:Estrogen is closely correlated with obesity,and they both positively related to the growth and development of uterus and endometrial proliferation.