Objective To investigate the value of detection of pelvic floor ultrasound parameters combined with serum relaxin(RLX)and estradiol(E2)levels in diagnosis of female stress urinary incontinence(SUI).Methods A total of 127 puerperae with SUI were selected as SUI group,and another 127 puerperae without SUI during the same period were selected as control group.The pelvic floor ultrasound parameters[bladder neck descent(BND),postvoid residual angle of the bladder-u-rethra(PUVA),and urethral rotation angle(URA)]and serum RLX and E2 levels were compared between the two groups.Binary Logistic regression analysis was used to screen independent influen-cing factors of female SUI,and the diagnostic efficacy of each index alone and their combination for female SUI was analyzed through the receiver operating characteristic(ROC)curve.Results The BND,PUVA,and URA values in the SUI group were greater than those in the control group,the ser-um RLX level was higher,and the serum E2 level was lower,with statistically significant differences(P＜0.05).Binary Logistic regression analysis showed that BND,PUVA,and E2 were independent influencing factors of female SUI(P＜0.05).ROC curve analysis revealed that the areas under the curve(AUCs)for the diagnosis of female SUI by BND,PUVA,URA,RLX,and E2 alone and their combination were 0.775,0.814,0.777,0.749,0.746,and 0.932,respectively.Their sensitivities were 90.6％,86.6％,57.5％,48.8％,100.0％,and 92.1％,and the specificities were 53.5％,68.5％,91.3％,92.1％,49.6％,and 77.2％,respectively.Conclusion The com-bined detection of pelvic floor ultrasound parameters including BND,PUVA,URA,and serum RLX and E2 levels has a high diagnostic value for female SUI.