Objective To compare the clinical values of dynamic magnetic resonance imaging (MRI) and transperineal ultrasonography (TLUS) in the diagnosis of pelvic organ prolapse (POP).Methods A prospective study was conducted on 139 patients with suspected POP who were admitted to our hospital from May 2019 to November 2021. All patients underwent MRI, TLUS, and Pelvic Organ Prolapse Quantification (POP-Q) examination, and their diagnostic results were recorded. The diagnostic results of MRI and TLUS for POP were analyzed.Results The 139 patients with suspected POP were evaluated via POP-Q, which identified 21 cases without organ prolapse, 23 with uterine prolapse, 38 with cystocele, and 57 with uterine prolapse combined with cystocele. MRI diagnosis showed 99 cases of cystocele, 64 cases of uterine prolapse, 67 cases of enterocele, and 81 cases of rectocele. TLUS diagnosis showed 121 cases of obvious organ prolapse including 53 cases of single-compartment prolapse and 68 cases of multi-compartment prolapse, 98 cases of obvious cystocele, 82 cases of obvious uterine prolapse, and 29 cases of excessive perineal descent. Pearson correlation analysis demonstrated that the parameters of the anterior, middle and posterior compartments determined via POP-Q were positively correlated with those measured via MRI and TLUS. (P < 0.05). The sensitivity and specificity of TLUS for diagnosing obvious cystocele were 96.84% and 86.36%, while those of MRI were 97.89% and 86.36%, respectively. There was no difference in the sensitivity and specificity for diagnosing obvious cystocele between the two approaches (P > 0.05). The sensitivity and specificity of TLUS for diagnosing obvious uterine prolapse were 97.50% and 91.53%, while those of MRI were 97.50% and 93.22%, respectively. There was also no difference in the sensitivity and specificity for diagnosing obvious uterine prolapse between the two approaches (P > 0.05).Conclusions The diagnostic results of POP via MRI and TLUS are significantly correlated with those via POP-Q. MRI and TLUS outweigh POP-Q in the assessment of posterior pelvic prolapse, and can be established as effective supplements to the POP-Q assessment of POP. The combination of MRI or TLUS with POP-Q improves the accuracy of diagnosing POP.