During the surgery of intracranial aneurysm, there is a risk of rupture and bleeding of the aneurysm. We use a combination of interventional and microscopic techniques to perform large aneurysm surgery, and achieve good results. The aneurysm we treated was between 2.5 and 3.5 cm in diameter, and on the day of surgery, a double-lumen balloon catheter (CBP, with one lumen being the non-detachable balloon attached to the tip of the catheter and the other being the middle lumen, the catheter lumen through the balloon) was inserted in the catheterization room through the femoral artery and the balloon end was delivered to the rocky section of the internal carotid artery on the affected side. After satisfactory placement, the catheter was sent to the operating room. The operation was performed by conventional craniotomy using the wing point approach. After opening the lateral fissure, the arachnoid is separated from the proximal to the distal end of the internal carotid artery, and the arachnoid membrane is separated by a sharp method, and the carotid pool is opened to gradually release the cerebrospinal fluid to reduce the intracranial pressure, and some of the bone is removed with a grinding drill if necessary. At this time, the balloon filled with CBP blocked the blood flow of internal carotid artery, and the intra-aneurysmal pressure decreased significantly, and the aneurysm body could be retracted by pulling the brain pressure plate. Good results were eventually achieved. Preoperative CT film Preoperative MRI Preoperative DSA Postoperative CTA disappearance of aneurysm shadow