Objective: To analyze the risk factors of transient neurological deficits (TND) and perioperative stroke in patients with MMD after extracranial–intracranial revascularization. Methods: A retrospective analysis of the clinical data of 183 patients with MMD undergoing 203 EC–IC bypass operation procedures from January 2018 to August 2020. According to whether TND and stroke occurred within 14 days after operation, univariate analysis and multivariate logistic regression were used. Results: TND occurred in 26 cases (12.8%) of revascularization. The results of the univariate analysis showed that history of diabetes, multiple episodes of preoperative symptoms, lesions involving the posterior circulation, and high postoperative blood pressure are the risk factors of TND. Further multivariate logistic regression analysis showed that multiple episodes of preoperative symptoms (p = 0.016) and lesions involving the posterior circulation (p = 0.014) are the independent risk factors for TND. Perioperative stroke occurred in 12 cases (5.9%). The results of the univariate analysis showed that older age, history of hypertension, preoperative cerebral infarction as the main symptom, lesions involving the posterior circulation, and high perioperative blood pressure are the risk factors of perioperative stroke. The results of multivariate logistic regression analysis showed that preoperative cerebral infarction as the main symptom (p = 0.015) is an independent risk factor for perioperative stroke. The occurrence of perioperative complications was not related to the improvement of follow-up mRS (Modified Rankin Scale) score and long-term cerebral rehemorrhage. Conclusions: Clinically, patients with MMD have multiple episodes of preoperative symptoms, lesions involving the posterior circulation, and preoperative cerebral infarction and should be attached when undergoing revascularization.