Objective To investigate the evaluation of the bladder neck descent(BND) in the diagnosis of female stress urinary incontinence(SUI). Methods Transperineal real-time three-dimensional ultrasound were performed in 244 cases of normal women and 95 cases of female patients with stress urinary incontinence in resting condition and Valsalva condition, the bladder neck descent(BND) were observed and evaluated. The clinical diagnosis were used as the reference standard. And the diagnostic accuracy and diagnostic c...