The aim of this study was to investigate the role of Von Willebrand Factor/thrombospondin type I repeats-13 (VWF/ADAMTS13) balance in aSAH. Fifty eight patients with aSAH at the First Affiliated hospital of Soochow University, Suzhou, China, between January 2012 and January 2014 were eligible for the study. They were divided into delayed cerebral ischemia group (DCI group) and non-delayed cerebral ischemia group (no DCI group), or cerebral vasospasm group (CVS group) and no spasm group (no CVS group), or good outcome group and poor outcome group. The control group consisted of twenty healthy people. All patients underwent CT, DSA, or (and) CTA diagnosed with intracranial subarachnoid hemorrhage which is caused by aneurysm rupture. Venous blood was drawn in tubes at 3 time points: 1 day after SAH (T1), (4±1) days after SAH (T2), and (9±1) days after SAH (T3) to determine plasma concentrations of ADAMTS13, VWF, P-selectin and IL-6 via enzyme-linked immunosorbent assay (ELISA). Transcranial doppler sonography (TCD) was used to measure mean blood flow velocity of the middle cerebral artery (VMCA). Glasgow Outcome Scale (GOS) was measured before discharge. Among 58 patients, 12 (20.7%) had DCI, 40 (68.9%) had TCD evidence of CVS, and 20 (34.5%) had poor outcome. The concentrations of VWF, P-selectin and IL-6 on T1, T2 and T3 after SAH were significantly higher in DCI, CVS and poor outcome groups compared with those of the control group (P < 0.05). The concentrations of VWF, P-selectin and IL-6 were significantly higher in DCI, CVS and poor outcome groups compared with those of the no DCI, no CVS and good outcome groups. The activity of ADAMTS13 was lower in DCI and poor outcome groups compared with those of the no DCI and good outcome groups (P < 0.05). The activity of ADAMTS13 showed no difference in CVS group and no CVS group (P > 0.05). The results of our study suggest that the increased VWF and decreased ADAMTS13 activity were associated with DCI and poor outcome. The balance of VWF/ADAMTS13 could be used to predict the clinical outcome. The deficiency of ADAMTS13 can not only induce DCI but also accelerate inflammatory reaction. Our results reported in this paper may provide new insights into the possible use of ADAMTS13 as a therapeutic agent in aneurysmal subarachnoid hemorrhage.