Abstract:【Objective】 To investigate the effect of extracranial and intra arterial (IC-EC) artery bypass grafting in the treatment of complex middle cerebral artery aneurysms. 【Methods】 The clinical data of 22 patients with complex middle cerebral aneurysms treated in our hospital from January 2014 to January 2018 were retrospectively analyzed. IC-EC artery bypass grafting was performed. The prognosis of patients was evaluated by mRS score, and the living ability of patients was evaluated by daily living scale (ADL). DSA examination confirmed the patency after vascular reconstruction, including regional cerebral blood volume (rCBV), relative time to peak (RTTP), relative mean transit time (rMTT).【Results】 DSA was reexamined in all patients 1-2 weeks after operation. The results showed that the parent artery was completely occluded, the blood flow was unobstructed, and there was no death case.The mRS score at 7 days and 3 months after operation was significantly lower than that before operation, while the ADL score was significantly higher than that before operation (P<0.05); the mRS score of 3 months after operation was significantly lower than that of 7 days after operation, and the ADL score was significantly higher than that of 7 days after operation, the differences were statistically significant (P<0.05). The rCBV of 7 days and 3 months after operation was significantly higher than that before operation, while rMTT and rTTP were significantly lower than those before operation (P<0.05); rCBV of 3 months after operation was significantly higher than that of 7 days after operation, while rmtt and rTTP were significantly lower than 7 days after operation, the differences were statistically significant (P<0.05).【Conclusion】 IC-EC artery bypass grafting has a good effect in the treatment of MCA aneurysms, which is worthy of clinical use.