Objective To evaluate the value of Compas technique( computed optimun method for profile angle of singht,Compas) in displaying intracranial aneurysms. Methods DSA images of 31 cases of subarachnoid hemorrhage diagnosed by CT were studied. The DSA images in routine A-P and Lateral projections were compared with the images obtained by Compas technique in the same equipment. Results 23 of 31 were diagnosed as intracranial aneurysms by Compas and confirmed by operation, while only 5 were diagnosed definitely with routine A-P & Lateral projections. The other 18 studies were discovered as blurred margin of the artery but indefinite for the diagnosis of aneurysms. There is a statistical difference between the two methods. ?~2=14.93,P