Objective To investigate the application effect of anterior clinoid process drilled off via epidural approach in posterior communicating artery aneurysm ( PCoAA) clipping. Methods The clinical data of 42 patients with PCoAA who underwent craniotomy from January 2012 to January 2014 were analyzed retrospectively,including 22 patients performed anterior clinoid process drilled off and 20 did not. The difficult or easy degree of intraoperative aneurysm clipping and postoperative efficacy were analyzed. Results The aneurysms in 22 patients underwent anterior clinoid process were clipped satisfactorily. The brain retractor was not used during the procedure. Only one patient had cerebral infarction after procedure. No patients had oculomotor nerve paralysis and incomplete clipping of aneurysms. Of the 20 patients without the anterior clinoid process drilled off,3 aneurysms were clipped incompletely because it was difficult to implant aneurysm clips, 2 had cerebral infarction, and 1 had oculomotor nerve paralysis. Conclusion Removing the anterior clinoid process drilled off via extradural approach may bring convenience for PCoAA clipping. It can effectively avoid the difficulty of implanting aneurysm clips during the procedure. Its application is safe and can reduce postoperative complications.