Objectives:To observe the changes of serum reproductive hormone in erectile dysfunction (ED) patients,inn order to assess the correlation between serum reproductive hormone and ED patients.Methods:A cross-sectional randomized study of 3000 men aged from 40 to 80 years was performed in Shanghai and Zhejiang community.The erectile function (EF) was evaluated by International Index of Erectile Function 5 (IIEF-5).The serum total testosterone (TT),luteinizing hormone (LH) and sex hormone-binding globulin (SHBG) were measured by chemilum inescentenzyme immunoassay (CLIA) method,while testosterone secreting index (TSI),free testosterone (FT) and bioavailable testosterone (Bio-T) were calculated respectively.Results:The prevalence of ED was 76.75% in eastern China,of which the rates of mild,moderate and severe ED were 47.56%,10.41% and 18.78% respectively.The concentration of TSI,Bio-T and SHBG were closely correlated with IIEF score on ED domain (P < 0.0001),but this was not the case with TT.Pearson regression analysis revealed that the concentration of TSI,Bio-T and SHBG were significantly related to IIEF score,but not with TT.Conclusion:Both SHBG and Bio-T is much more effective than serum TT in diagnosis of ED.TSI/Bio-T declining and SHBG increasing plays a critical role in reflecting the testerone level of ED patients.