Objective To discuss the application of three-dimensional CT angiography (3D-CTA) and skull reconstruction in determination of the precise location of the lateral fissure and entry angle, and to clip middle cerebral artery bifurcation aneurysms.Methods The clinical data of 23 patients with middle cerebral artery bifurcation aneurysms were retrospectively analyzed. These patients consisted of 10 males and 13 females, with a mean age of 52 years. Preoperative 3D-CTA and skull reconstruction were performed for all patients. The bony marker was set at the turning point of the sphenoid ridge towards the middle cranial fossa. The lateral fissure was separated and the aneurysm was clipped after determination of the precise location of the aneurysm, lateral fissure, and entry angle referring to the bony marker.Results In the 23 patients with cerebral aneurysms, the aneurysms, M1 bifurcations, and M1 ends were successfully exposed with a lateral fissure length of 1.5~2.0 cm, an entry angle of 45 degrees, and a lateral fissure depth around 1.5 cm. The aneurysms in all patients were successfully clipped. The reexamination of the skull by CTA after surgery showed that all aneurysms disappeared and the artery with aneurysm was clear. The postoperative one-month follow-up revealed Glasgow Outcome Scale scores above 4 in all patients.Conclusions Determination of the precise location of the lateral fissure and entry angle using 3D-CTA and skull reconstruction can help to clip the middle cerebral artery bifurcation aneurysms with a small lateral fissure and achieve satisfactory treatment outcomes.