Objective:To investigate the preoperative evaluation, safety and clinical efficacy of intravascular recanalization for patients with symptomatic non-acute middle cerebral artery occlusion .Methods:Twenty-six patients with symptomatic non-acute middle cerebral artery occlusion admitted between January 2018 to June 2021 were retrospectively analyzed. The clinical symptoms, cerebral perfusion, occlusive site, occlusive length, collateral circulation and distal capillary were evaluated. There were 17 cases accorded with intravascular recanalization. The cerebral blood flow , cerebral blood volume, MTT, peak time and scores of 17 patients before and after revascularization were compared by paired t test.Results:Endovascular recanalization was performed in 17 patients and extracranial-intracranial artery bypass grafting was performed in 9 patients. Among the 17 cases, there were 7 cases of hemiplegia of contralateral limbs, 6 cases of recurrent cerebral infarction, 4 cases of paroxysmal contralateral limb numbness or weakness, 3 cases of cognitive dysfunction and 3 cases of headache. The cerebral perfusion of the occluded side of the middle cerebral artery in 17 cases was significantly lower than that of the healthy side. One patient failed to pass through the occlusion with micro guide wire, and gave up the operation after repeated attempts. The occluded vessels were successfully recanalized in 16 cases (thrombolytic grade of cerebral infarction=2b-3), and recanalized in 16 cases, including 9 cases of simple balloon dilatation and 7 cases of stent implantation. Three months after the operation, the National Institute of Health Stroke Scale (NIHSS) score of 17 patients decreased from (9.57±2.32) to (3.75±1.42). The cerebral blood flow, cerebral blood volume, mean transit time and peak time were also significantly improved compared with those before the operation（ t value was 9.08，5.54，4.26，8.56，6.00，respectively，all P<0.001）. The Montreal Cognitive Assessment (MoCA) score of cognitive function was (22.70±1.70) before the operation, and there months after operation (26.30±2.30) points ( t=6.66, P<0.001) were statistically significant. After operation, CT cerebral angiography or whole cerebral angiography showed that 1 case was occluded, 15 cases had good recanalization, no intracranial hemorrhage occurred during the perioperative period, and no new stroke occurred during the 6-month follow-up period. Conclusion:For patients with symptomatic non acute middle cerebral artery occlusion, the patients who may benefit from multi-dimensional evaluation are selected for intravascular recanalization treatment. There are few complications and high recanalization rate. The short-term follow-up clinical effect is good, but the long-term effect needs to be further observed.