Objective:To explore the ERRα expression in cardinal ligament and the effect of 17-β estradiol(17-βE2) on the proliferation of fibroblasts derived from cardinal ligament in patients with uterine prolapse. Methods:The tissues of cardinal ligament were collected from 10 patients with uterine prolapse and 10 normal controls for the detection of ERRα expression by flow cytometry;total of 10 cell strains of cardinal ligament fibroblasts derived from patients with uterine prolapse were established by primary cell culture and were treated with different concentrations of 17-βE2 (0 nmol/L,0.1 nmol/L,1.0 nmol/L,10.0 nmol/L,100.0 nmol/L) for 48 h. The effect of E2 on cell proliferation was then measured by the proliferous index(PI). Results:① ERRα were expressed in cardinal ligament of patients with uterine prolapse and normal controls,and the ERRα expression level of cardinal ligament was higher in normal controls than that in patients with uterine prolapse(P < 0.05). ② The PI of fibroblasts at 10.0 nmol/L 17-βE2 concentration was higher than that of control. The PI of fibroblasts at 100.0 nmol/L 17-βE2 concentration was lower than that of control. Conclusion:①The ERRα expression level of cardinal ligament decreased in patients with uterine prolapse. ② The effect of different concentrations of 17-βE2 on the proliferation of fibroblasts derived from cardinal ligament in patients with uterine prolapse was different:17-βE2 promoted fibroblasts proliferation at concentration of 10.0 nmol/L,but it induced apoptosis of the cells at 100.0 nmol/L concentration.