Objective: To evaluate the value and prognosis of four-dimensional pelvic floor ultrasonography in female pelvic floor dysfunction (PFD). Materials and Methods: Ninety postpartum women diagnosed with PFD in this hospital from December, 2016 to February, 2018 were selected for inclusion in this study. These women were divided into vaginal delivery and selective cesarean section groups. In addition, 45 women without PFD were selected as the control group. Four-dimensional pelvic floor ultrasound was used to diagnose the difference between the pelvic floor and pelvic diaphragm before and after resting state, tension, and anal contraction. Results: BSD, bladder neck movement length, and urethral posterior horn in the vaginal delivery group were significantly higher than those measured in the cesarean section (p < 0.05). The transverse diameter, anterior and posterior diameter of the diaphragm, and the thickness of the anal muscle were significantly higher in the vaginal delivery group than measurements made in the control group. Within the selective cesarean section group, the transverse diameter, anterior and posterior diameter of the diaphragm, and the thickness of the anal muscle were significantly higher (p < 0.05) in patients conducting a Valsalva maneuver than in the control group. Conclusion: The use of pelvic floor ultrasonography for patients with pelvic functional disorders has a high diagnostic coincidence rate. It can clearly display the pelvic cavity of the parturient and provide critical insight into the patient’s condition, thus providing a reliable basis for patient treatment.