This study aimed to investigate the diagnostic value of transvaginal color Doppler ultrasonography and imaging indicators in polycystic ovary syndrome (PCOS). In this case-control study, 100 PCOS patients (PCOS group) and 100 healthy subjects (control group) were selected. The total ovarian area, ovarian medullary area, peak systolic velocity (PSV), end-diastolic blood flow velocity (EDV), and resistance index (RI) were compared. The total ovarian area, ovarian medullary area, PSV, and EDV of PCOS patients were significantly higher than healthy subjects (P <.01). The RI of PCOS patients was significantly lower (P <.01). Each parameter was evaluated separately by receiver operating characteristic analysis: total ovarian area (area under the curve [AUC] 0.999), ovarian medullary area (AUC 1.000) and RI (AUC 0.997) showed the highest diagnostic performance, followed by EDV (AUC 0.877) and PSV (AUC 0.631). Transvaginal ultrasound, especially 2-dimensional morphological parameters, demonstrated high discriminative ability for PCOS. However, given the study population and potential incorporation bias, these results require external validation in broader cohorts.