Objective To investigate the reversal effect of intravenous injection of erythropoietin on vasospasm in the basilar artery in rabbits subjected to subarachnoid hemorrhage (SAH). Methods Thirty male New Zealand adult white rabbits weighing 2.0-2.5 kg were equally randomized into 5 groups: sham-operated group, SAH0 group, SAH1 group, SAH2 group and SAH3 group. SAH models of single-hemorrhage were established by injecting autologous arterial blood (1.0 mL/kg) into the cistema magna in SAH group's rabbits, while animals in the sham-operated group received an injection of normal saline (1.0 mlAg). Twenty-four h after SAH, rabbits in the sham-operated group and the SAHO group were received intravenous injection of normal saline (0.1 mL/kg), meanwhile, intravenous injection of r-Hu-EPO at dosages of 500,1000, or 2000 IU/kg was initiated in the SAH1 group, SAH2 group SAH3 group, respectively. All animals were sacrificed by perfusion-fixation 48 h after SAH induction. The cross section areas of basilar arteries, corrugation coefficient (CC) of the basilar arteries, and hippocampus normal neuron density of CA1 area were measured by Image-Pro-Plus software. Results Morphology observation on the basilar arteries showed no obvious changes in the sham-operated group, significantly thickened and disorganized vascular walls with thickened tunica media and disorganized smooth muscle in the SAH0 and SAH1 groups; the internal elastic lamina in the SAH3 group was folded. Compared with that in SAH0 group [(0.07±0.02) mm2], the cross-sectional area of basilar arteries in SAH2 [(0.10±0.01) mm2] and SAH3 [(0.16±0.02) mm2] groups were significantly increased (P<0.05); the CC in SAH2 (1.22± 0.06) and SAH3 (1.15±0.03) groups was significantly lower than that in the SAHO group (1.31±0.09, P<0.05); and the normal neural density of hippocampus in CA1 area in the SAH3 group [(126.8±5.7) cell/mm] was significantly higher than that in the SAHO group [(99.3±9.6) cell/mm, P<0.05]. Conclusion A single intravenous injection of erythropoietin 24 h after SAH can still reverse SAH-induced vasospasm and attenuate injury of neurons.