Background: Currently, no clear diagnostic indicator of vertebral artery hypoplasia (VAH) or intracranial stenosis exists in clinic. This study aims to study the feasibility of neck-brain integrated ultrasound for evaluating stenosis of the intracranial segment in the vertebral artery by comparing with those of computed tomography angiography (CTA) and digital subtraction angiography (DSA). Methods: Clinical data of 138 patients who presented to our hospital with dizziness and headache as the main symptoms between April 2018 and June 2019 were retrospectively analyzed. Patients were divided into observation group and unilateral VAH group. The diagnosing accuracy of ultrasound, CTA, and DAS, the vertebral artery diameter (VAD), blood flow, end diastolic velocity (EDV), peak systolic velocity (PSV) values, resistance indexes (RIs), and difference of RI were compared between the two groups. The sensitivity, specificity and accuracy of ultrasound hemodynamic indicators in assessing stenosis of the intracranial segment of the vertebral artery were calculated.Results: The accuracy rates of mild stenosis and non-stenosis with neck-brain integrated ultrasound were significantly different from those with CTA and DSA examination (P<0.05). The VAD, blood flow, EDV and PSV values of the affected side in the observation group were lower than those of the VAH side in the unilateral VAH group, while the RI and RI difference value were significantly higher than the unilateral VAH group (P<0.05). When the predicted boundary value was 2.084 mm (VAD), 56.41 mL/min (blood flow), 8.47 cm/s (EDV), 0.743 (RI), and 0.149 (difference of RI), the sensitivity and specificity were (86.43%, 49.45%), (88.67%, 47.42%), (80.47%, 68.71%), (82.71%, 84.66%), and (95.84%, 80.11%), respectively.Conclusions: Neck-brain integrated ultrasound is of great value as a noninvasive examination in the diagnosis of stenotic lesions of the internal cervical vertebral artery. VAD, EDV, blood flow, RI, and the difference in RI can be used as indicators to evaluate stenosis of the internal carotid segment of the vertebral artery and provide a reliable basis for the clinical diagnosis of posterior circulation ischemia.