Objective To evaluate the anorectal angle (ARA) and its changes at rest, during contraction and Valsalva maneuver by pelvic floor ultrasound. And to explore its relationship with the degree of uterine prolapse.Methods A total of 131 women who underwent pelvic floor ultrasound examination in our hospital were divided into no prolapse group (47 cases), stage I prolapse group (40 cases), and stage II or above prolapse group (44 cases) based on the degree of uterine prolapse. Pelvic floor ultrasound was used to measure ARA at rest, during contraction and Valsalva maneuver in each group. ARA and its changes in different states were compared, and its relationship with the degree of uterine prolapse was analyzed.Results There was a statistically significant difference in vARA and ARA changes during Valsalva maneuver among the three groups (all P＜0.001). Compared with the no prolapse group, the vARA of the stage I prolapse group decreased, while the vARA of the stage II or above prolapse group increased, with statistical significance (both P＜0.05). Compared with the stage I prolapse group, the vARA of the stage II or above prolapse group increased, with statistical significance (P＜0.05). During Valsalva maneuver，ARA decreased in the stage Ⅰ group，and increased in the no prolapse group and the stage Ⅱ group（both P＜0.001）.ARA increased more in the stage II group（P=0.004）.Conclusion The application of pelvic floor ultrasound can evaluate the ARA and its changes in patients with varying degrees of uterine prolapse. ARA and its changes in Valsalva maneuver are related to the degree of uterine prolapse and have certain clinical value.