This retrospective cohort study aims to explore the clinical value of urodynamics in evaluating lower urinary tract function in pelvic organ prolapse (POP) patients, and to investigate the urodynamic characteristics of POP patients with occult stress urinary incontinence (OSUI) in whom moderate or above postoperative SUI eventually occurred after prolapse surgery. The medical records of 626 advanced POP patients who underwent vaginal pelvic reconstructive surgery were analyzed. The patients with anterior compartment prolapse were more susceptible to urodynamic changes than those with apical or posterior compartment prolapse (95.1% vs. 40.15%). The proportion of patients with urodynamic abnormality was increased with prolapse severity (68.8% vs. 78.6%). After 3 months, the incidence of moderate or severe postoperative urinary incontinence in the OSUI patients was 20%, while it is 2.8% in non-OSUI patients. In subgroup analysis of OSUI patients, the urodynamics of patients with moderate or above postoperative urinary leakage showed significantly lower Valsalva leak point pressure (VLPP), maximum urethral closure pressure (MUCP), maximal bladder volume (MBV) and maximum urine flow rate (MUFR). For POP patients with OSUI, anti-incontinence surgery is only recommended for whom with lower VLPP, MUCP, MBV and MUFR to avoid the risk and costs of secondary surgery or overtreatment.