Objective:To investigate the distribution of polymorphism of estrogen receptor (ER) gene in postmenopausal Han women in Beijing as well as its relationship with bone mineral density (BMD).Methods:Xba Ⅰ,and Pvu Ⅱ polymorphisms of ER gene were studied by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) and BMD were determined by DEXA (dual-energy X-ray absorptiometry).The relationship between BMD and polymorphism of ER gene was studied by variance analysis.Results:Pvu Ⅱ polymorphism of ER gene was not associated with BMD of spongy and compact bone of radius;while Xba Ⅰ polymorphism of ER gene was associated with BMD of spongy and compact bone of radius.The lowest BMD was found with XX genotype while the highest BMD was found with xx genotype.Conclusion:There is high correlation between of Xba Ⅰ polymorphism and BMD of spongy and compact bone of radius.Our study suggested some bases to explore the pathogenesis of osteoporosis and to prevent the development of osteoporosis.