Objective: For patients with early acute cerebral infarction (ACI), transcranial Doppler ultrasound was used in the clinical examination, and its application effect was observed and analyzed. Methods: This study was carried out between October 2018 and October 2019. 50 patients with ACI included as the research object was evaluated by transcranial Doppler and CT examination, and the application of the two examination methods was compared. Results: The results of transcranial Doppler examination showed that the abnormal rate of blood flow velocity and the ratio of both sides (VACA) in patients with early ACI was higher than that of CT examination. Conclusion: With the impact on the location and area of vascular occlusion in patients, VACA can effectively reflect the status and effectiveness of the collateral circulation function of the patient’s pia vessels during cerebral infarction.