Objective To study the feasibility and efficacy of different endovascular embolization methods for the treatment of very small intracranial aneursms.Methods A retrospective analysis was made on the basis of the clinical data of 43 patients with very small intracranial aneurysms (51 lesions) from 686 cases of patients with intracranial aneurysms.There were 19 male cases and 24 female.Among them,5 cases were multiple aneurysms.Endovascular interventional treatments,such as simple coil embolization,stent-assisted coil embolization and Onyx glue embolization,were performed.All patients were followed-up.Results In 51 aneurysm lesions,27 received simple coil embolization,9 stent-assisted coil embolization,3 simple stent placement within the parent artery and 12 Onyx glue embolization.In these cases,except 3 lesions with simple stent placement within the parent artery,30 aneurysms to grade zero embolism,11 to grade Ⅰ,7 to grade Ⅱ.1 patient had acute thrombosis and received urokinase thrombolytic recanalization.1 patient had intraoperative bleeding and postoperative coma,and got 4 of GOS score after treatment.The postoperative vasospasm was observed in 3 cases and transient hemiplegia occurred.All patients were followed-up for an average of 40.6 months (3-72 months).Rebleeding occurred in 1 patient.36 cases underwent reexamination of angiography and had no recurrence.In 1 case,the coils partially prolapsed to the parent artery.Conclusions The accurate diagnosis of mirco-intracranial aneurysms requires high rows of CTA and/or 3D-DSA.The endovascular treatment is effective for the treatment.For those mirco-intracranial aneurysms which locate beyond stage Ⅳ,Onyx glue aneurysm embolization is recommended,but its long-term effect still needs further follow-up for more accurate conclusions.