Aim To study the effects of neferine (Nef) on constraction of the rabbit basilaris arteria Induced by phenylephrine (Phe). Methods The blood vessel tension responses to drug were measured by rabbit basilaris arteria rings (RBAR) endothelium being removed and intact endothelium in vitro. Results The RBAR precontracted with Phe can be relaxed by Nef with a significant difference from saline control group (p<0.001). The vasodilatation of Nef was not significantly differences between the endothelium removed and intact endothelium groups (p>0.05). Conclusions The RBAR precontracted with Phe can be relaxed by Nef in vitro. The vasodilatation of Nef is independent of endothelium.