Objective To examine the prognostic value of flow diversion (FD) presented on transcranial Doppler ultrasound (TCD) in patients with large hemispheric infarction (LHI) caused by the unilateral middle cerebral artery (MAC) occlusion.Methods Seventy-three consecutive LHI patients who had occlusion in M1 segment of MAC and were admitted to neurological intensive care unit at Xijing Hospital from January 2012 to June 2016 were reviewed.All the participants had TCD examination after admission,and were grouped according to the presence or absence of FD into FD+ and FD-.Three-month,six-month,and twelve-month functional outcomes of all the participants were collected and analyzed.Long-term survival rates were compared using Kaplan-Meier survival analysis.Receiver operating characteristic curve (ROC) was used to examine the predictive power of FD in patients with LHI.Results Among 73 LHI patients,28 (38.36％) patients were presented with FD.The incidence rates of cerebral herniation,usage of mechanical ventilation,mortality during hospitalization and incidence rates of three-month,six-month and twelve-month poor outcomes were much higher in patients without FD than those with FD.Multivariate analyses demonstrated that FD was independently associated with cerebral herniation (OR=28.943,95％CI 1.922-435.918,P=0.015),usage of mechanical ventilation (OR=11.151,95％CI 1.614-77.018,P=0.014),three-month (OR=20.163,95％CI 3.048-133.362,P=0.002),six-month (OR=3.525,95％CI 1.153-10.773,P=0.027),and twelve-month (OR=4.400,95％CI 1.387-13.960,P=0.012) poor outcomes.FD yielded an area under the ROC of 0.756,allowing for prediction of three-month outcomes of LHI.Conclusion FD presented on TCD is an early predictor of outcomes in patients with LHI.