Purpose To investigate the diagnostic criteria and value of angle parameters in female stress urinary incontinence (SUI),and to provide an objective basis for clinical diagnosis of SUI.Materials and Methods In retrospective analysis,138 patients with SUI diagnosed by clinic from December 2014 to December 2016 were selected as the study group,while 100 normal females receiving the routine medical examination were selected as the control group.All subjects in both groups were examined by pelvic floor ultrasound to observe the urethral inclination angle,urethral rotation angle (URA) and posterior urethrovesical angle (PUVA) to obtain the standard in diagnosis of female SUI.30 SUI patients from January to February 2017 were prospectively analyzed,and the above results were verified to evaluate their value in the diagnosis of SUI.Results There was no significant difference in age,body mass index,gravidity and parity history and resting state PUVA between the two groups (P＞0.05).There was significant difference in the resting state urethral inclination angle,Valsalva urethral inclination angle,PUVA and URA between the two groups (P＜0.05).The receiver operating characteristic curve was used to find the cut-off value of SUI:urethral inclination angle in resting state ＜14.5°,urethral inclination angle in Valsalva state ＞32.5 °,and URA ＞49.5 °,PUVA ＞154.5 °,with their sensitivity of 62％,73％,67％ and 57％,respectively;the specificity of 61％,84％,82％ and 70％,respectively;and the area under the curve of 0.633,0.809,0.768 and 0.658,respectively.By verification,when the urethral inclination angle was 14.5° in the resting state,the coincidence rate of the diagnosis of SUI was 63％;when the urethral inclination angle of Valsalva was 32.5°,83％;when the URA was 49.5°,77％;when the PUVA was 154.5 °,60％.Conclusion Pelvic floor ultrasound can clearly observe angle parameters of females,the determination of the cut-off value of ultrasound is helpful for clinical diagnosis and evaluation of SUI,and the urethral inclination angle in Valsalva state and URA are of high diagnostic value in the diagnosis of female SUI,providing an objective basis for clinical diagnosis of SUI.