Aims To evaluate pulsatility index (PI) in patients with acute ischemic stroke (AIS) who underwent endovascular thrombectomy (EVT). Methods Patients were retrospectively recruited if their stroke were secondary to middle cerebral artery (MCA) occlusion and achieved full recanalization after EVT. Transcranial Doppler was performed within 24-hour post-EVT. The primary outcome was correlation between the MCA-PI on the affected side and 3-month functional outcome, with modified Rankin scale (mRS) >= 5 indicated extremely poor functional outcomes. Results Totally, 170 patients were included. High MCA-PI was positively related to the 3-month mRS score (r = 0.288, p < 0.001). The highest quartile of the MCA-PI was associated with a high incidence of extremely poor functional outcomes (adjusted OR, 13.33; 95% CI, 2.65-67.17; adjusted p = 0.002) after adjusting for confounding factors. The predictive capacity of the MCA-PI for extremely poor functional outcomes was good (area under the curve, 0.755; 95% CI, 0.655-0.854; p < 0.001), and its cutoff value for predicting extremely poor outcomes was 1.04, with a sensitivity of 65.6% and specificity of 78.3%. Conclusion The MCA-PI on the affected side is a prognostic biomarker in patients who have undergone stroke thrombectomy. An elevated MCA-PI may be prognostically valuable for predicting extremely poor functional outcomes.