We have conducted cervical imaging of uterine and micro-vessel flow velocity waveforms in acute pelvic inflammatory disease (PID) by transvaginal power Doppler ultrasound (TVPDU) in order to explore the associations of sonographic parameters with simple and complex cervicitis. Thirty-eight patients with acute PID (26 with acute simple cervicitis and 12 with complex cervicitis) were enrolled for an assessment of vascular grading of cervix and micro-vessel flow velocity using TVPDU before treatment. Seven parameters, including vascular grading (VG), lowest pulsatility index (PI), resistance index (RI), peak systolic velocity (PS), end diastolic velocity (ED), time average maximum velocity (TAMV), and vascular index (VI = PS/ED), were measured and recorded. Forty-one healthy patients were assessed as the control group. Vascular grading (VG) was significantly higher in the study group than the control group (p < 0.0001). The PI, RI, and VI were significantly lower in the study group than control group (p < 0.0001). No significant associations were observed between seven sonographic parameters and acute simple or/and complex cervicitis. For acute simple cervicitis, a PI cutoff of 1.1 had a sensitivity of 85.4% and a specificity of 92.1% (area under ROC curve [AUC], 93.2%). A RI of 0.6 had a sensitivity of 85.4% and a specificity of 78.9% (AUC, 86.1%). A VI of 2.6 had a sensitivity of 85.4% and a specificity of 78.9% (AUC, 84.9%). Power Doppler angiography of micro-vessel flow velocity waveforms in the cervix could represent a practical method to assist the diagnosis of pelvic inflammatory disease presented as acute cervicitis detected on transvaginal ultrasound before medical or surgical treatment. Cervical PI may be a useful index to detect micro-vessel flow velocity waveforms in acute cervicitis and differentiate acute simple cervicitis from complex cervicitis.