OBJECTIVE:　Multiple　intracranial　aneurysms　(MIA)　are　prevalent.　This　study　conducted　hemodynamic　calculations　on　MIA　to　analyze　the　effects　of　occlusion　of　the　internal　carotid　artery　(ICA)　and　middle　cerebral　artery　(MCA)　aneurysms　on　the　hemodynamics　of　other　arteries,　as　well　as　the　issue　of　the　treatment　order　for　these　aneurysms.　METHODS:　The　models　of　9　patients　with　MIA　were　selected　for　the　study.　A　computational　fluid　dynamics　model　combining　1-dimension　and　3-dimension　was　used　to　obtain　the　vascular　flow　pattern　and　wall　pressure.　RESULTS:　There　was　increased　pressure　at　the　MCA　and　anterior　cerebral　artery　(ACA)　after　occlusion　of　the　aneurysm　at　the　ICA.　However,　the　pressure　at　the　ICA　has　hardly　changed　after　the　aneurysm　occlusion　at　the　MCA.　Occlusion　of　the　aneurysm　of　different　sizes　at　the　MCA　had　almost　no　impact　on　the　pressure　at　the　ICA　and　ACA.　For　small　aneurysm,　the　pressure　of　the　ACA　and　MCA　increases　with　decreasing　size　of　the　aneurysm　at　the　ICA.　After　occlusion　of　a　large　aneurysm　at　the　ICA,　the　impact　on　the　pressure　of　the　ACA　and　MCA　is　almost　the　same　as　after　occlusion　of　a　medium-sized　aneurysm.　CONCLUSIONS:　If　the　treatment　order　of　ICA　and　MCA　aneurysms　cannot　be　determined　based　on　patient　factors　and　aneurysm　characteristics,　the　MCA　aneurysm　should　be　treated　as　a　priority.